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 /*
- * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 1998-2006 Apple Computer, Inc. All rights reserved.
  *
- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  * 
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License").  You may not use this file except in compliance with the
- * License.  Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
  * 
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
- * License for the specific language governing rights and limitations
- * under the License.
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
  * 
- * @APPLE_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
-#include <IOKit/IOService.h>
-#include <IOKit/IOLib.h>
-#include <IOKit/IOCommandQueue.h>
-#include <IOKit/IOCommandGate.h>
-#include <IOKit/IOTimerEventSource.h>
-#include <IOKit/IOWorkLoop.h>
-#include <IOKit/IOPlatformExpert.h>
+
+//#undef IOASSERT
+//#define IOASSERT    1
+
 #include <IOKit/assert.h>
+#include <IOKit/IOKitDebug.h>
+#include <IOKit/IOLib.h>
 #include <IOKit/IOMessage.h>
+#include <IOKit/IOPlatformExpert.h>
+#include <IOKit/IOService.h>
+#include <IOKit/IOEventSource.h>
+#include <IOKit/IOWorkLoop.h>
+#include <IOKit/IOCommand.h>
+
+#include <IOKit/pwr_mgt/IOPMlog.h>
 #include <IOKit/pwr_mgt/IOPMinformee.h>
-#include "IOKit/pwr_mgt/IOPMinformeeList.h"
-#include "IOKit/pwr_mgt/IOPMchangeNoteList.h"
-#include "IOKit/pwr_mgt/IOPMlog.h"
-#include "IOKit/pwr_mgt/IOPowerConnection.h"
-#include <kern/clock.h>
+#include <IOKit/pwr_mgt/IOPMinformeeList.h>
+#include <IOKit/pwr_mgt/IOPowerConnection.h>
+#include <IOKit/pwr_mgt/RootDomain.h>
+#include <IOKit/pwr_mgt/IOPMPrivate.h>
 
-#define super IORegistryEntry
+#include <sys/proc.h>
+#include <libkern/OSDebug.h>
 
-static void ack_timer_expired(thread_call_param_t);
-static void settle_timer_expired(thread_call_param_t);
-void PMreceiveCmd ( OSObject *,  void *, void *, void *, void * );
-static void PM_idle_timer_expired(OSObject *, IOTimerEventSource *);
-static void c_PM_Clamp_Timer_Expired (OSObject * client,IOTimerEventSource *);
-void tellAppWithResponse ( OSObject * object, void * context);
-void tellClientWithResponse ( OSObject * object, void * context);
-void tellClient ( OSObject * object, void * context);
-IOReturn serializedAllowPowerChange ( OSObject *, void *, void *, void *, void *);
-IOReturn serializedCancelPowerChange ( OSObject *, void *, void *, void *, void *);
+// Required for notification instrumentation
+#include "IOServicePrivate.h"
+#include "IOServicePMPrivate.h"
+#include "IOKitKernelInternal.h"
 
-extern const IORegistryPlane * gIOPowerPlane;
+static void settle_timer_expired(thread_call_param_t, thread_call_param_t);
+static void idle_timer_expired(thread_call_param_t, thread_call_param_t);
+static void tellKernelClientApplier(OSObject * object, void * arg);
+static void tellAppClientApplier(OSObject * object, void * arg);
 
+static uint64_t computeTimeDeltaNS( const AbsoluteTime * start )
+{
+    AbsoluteTime    now;
+    uint64_t        nsec;
 
-// and there's 1000 nanoseconds in a microsecond:
-#define ns_per_us 1000
+    clock_get_uptime(&now);
+    SUB_ABSOLUTETIME(&now, start);
+    absolutetime_to_nanoseconds(now, &nsec);
+    return nsec;
+}
 
+#if PM_VARS_SUPPORT
+OSDefineMetaClassAndStructors(IOPMprot, OSObject)
+#endif
+
+// Container class for recording system power events
+OSDefineMetaClassAndStructors( PMEventDetails, OSObject );
+
+//******************************************************************************
+// Globals
+//******************************************************************************
+
+static bool                  gIOPMInitialized   = false;
+static uint32_t              gIOPMBusyCount     = 0;
+static uint32_t              gIOPMWorkCount     = 0;
+static IOWorkLoop *          gIOPMWorkLoop      = 0;
+static IOPMRequestQueue *    gIOPMRequestQueue  = 0;
+static IOPMRequestQueue *    gIOPMReplyQueue    = 0;
+static IOPMWorkQueue *       gIOPMWorkQueue     = 0;
+static IOPMCompletionQueue * gIOPMFreeQueue     = 0;
+static IOPMRequest *         gIOPMRequest       = 0;
+static IOPlatformExpert *    gPlatform          = 0;
+static IOService *           gIOPMRootNode      = 0;
+
+static const OSSymbol *      gIOPMPowerClientDevice     = 0;
+static const OSSymbol *      gIOPMPowerClientDriver     = 0;
+static const OSSymbol *      gIOPMPowerClientChildProxy = 0;
+static const OSSymbol *      gIOPMPowerClientChildren   = 0;
+
+static uint32_t getPMRequestType( void )
+{
+    uint32_t type = kIOPMRequestTypeInvalid;
+       if (gIOPMRequest)
+        type = gIOPMRequest->getType();
+    return type;
+}
 
-// The current change note is processed by a state machine.
-// Inputs are acks from interested parties, ack from the controlling driver,
-// ack timeouts, settle timeout, and powerStateDidChange from the parent.
-// These are the states:
+//******************************************************************************
+// Macros
+//******************************************************************************
+
+#define PM_ERROR(x...)              do { kprintf(x); IOLog(x); } while (false)
+#define PM_LOG(x...)                do { kprintf(x); } while (false)
+
+#define PM_LOG1(x...)               do {  \
+                                    if (kIOLogDebugPower & gIOKitDebug) \
+                                        kprintf(x); } while (false)
+
+#define PM_LOG2(x...)               do {  \
+                                    if (kIOLogDebugPower & gIOKitDebug) \
+                                        kprintf(x); } while (false)
+
+#if 0
+#define PM_LOG3(x...)               do { kprintf(x); } while (false)
+#else
+#define PM_LOG3(x...)
+#endif
+
+#define RD_LOG(x...)                do { \
+                                    if ((kIOLogPMRootDomain & gIOKitDebug) && \
+                                        (getPMRootDomain() == this)) \
+                                        kprintf("PMRD: " x); } while (false)
+
+#define PM_ASSERT_IN_GATE(x)          \
+do {                                  \
+    assert(gIOPMWorkLoop->inGate());  \
+} while(false)
+
+#define PM_LOCK()                   IOLockLock(fPMLock)
+#define PM_UNLOCK()                 IOLockUnlock(fPMLock)
+#define PM_LOCK_SLEEP(event, dl)    IOLockSleepDeadline(fPMLock, event, dl, THREAD_UNINT)
+#define PM_LOCK_WAKEUP(event)       IOLockWakeup(fPMLock, event, false)
+
+#define ns_per_us                   1000
+#define k30seconds                  (30*1000000)
+#define kMinAckTimeoutTicks         (10*1000000)
+#define kIOPMTardyAckSPSKey         "IOPMTardyAckSetPowerState"
+#define kIOPMTardyAckPSCKey         "IOPMTardyAckPowerStateChange"
+#define kPwrMgtKey                  "IOPowerManagement"
+
+#define OUR_PMLog(t, a, b) \
+    do { gPlatform->PMLog( fName, t, a, b); } while(0)
+
+#define NS_TO_MS(nsec)              ((int)((nsec) / 1000000ULL))
+#define NS_TO_US(nsec)              ((int)((nsec) / 1000ULL))
+
+#if CONFIG_EMBEDDED
+#define SUPPORT_IDLE_CANCEL         1
+#endif
+
+#define kIOPMPowerStateMax          0xFFFFFFFF  
+
+#define IS_PM_ROOT                  (this == gIOPMRootNode)
+#define IS_ROOT_DOMAIN              (getPMRootDomain() == this)
+#define IS_POWER_DROP               (fHeadNotePowerState < fCurrentPowerState)
+#define IS_POWER_RISE               (fHeadNotePowerState > fCurrentPowerState)
+
+// log setPowerStates longer than (ns):
+#define LOG_SETPOWER_TIMES          (50ULL * 1000ULL * 1000ULL)
+// log app responses longer than (ns):
+#define LOG_APP_RESPONSE_TIMES      (100ULL * 1000ULL * 1000ULL)
+// use message tracer to log messages longer than (ns):
+#define LOG_APP_RESPONSE_MSG_TRACER (3 * 1000ULL * 1000ULL * 1000ULL)
 
 enum {
-    IOPMour_prechange_03 = 1,
-    IOPMour_prechange_04,
-    IOPMour_prechange_05,
-    IOPMour_prechange_1,
-    IOPMour_prechange_2,
-    IOPMour_prechange_3,
-    IOPMour_prechange_4,
-    IOPMparent_down_0,
-    IOPMparent_down_05,
-    IOPMparent_down_2,
-    IOPMparent_down_3,
-    IOPMparent_down_4,
-    IOPMparent_down_5,
-    IOPMparent_down_6,
-    IOPMparent_up_0,
-    IOPMparent_up_1,
-    IOPMparent_up_4,
-    IOPMparent_up_5,
-    IOPMparent_up_6,
-    IOPMfinished
-    };
-
-enum {                         // values of outofbandparameter
-       kNotifyApps,
-       kNotifyPriority
+    kReserveDomainPower = 1
 };
 
-struct context {               // used for applyToInterested
-    OSArray *  responseFlags;
-    UInt16     serialNumber;
-    UInt16     counter;
-    UInt32     maxTimeRequested;
-    int                msgType;
-    IOService *        us;
-    IOLock *   flags_lock;
-    unsigned long stateNumber;
-    IOPMPowerFlags stateFlags;
-};
+#define MS_PUSH(n)  \
+    do { assert(kIOPM_BadMachineState == fSavedMachineState); \
+         assert(kIOPM_BadMachineState != n); \
+         fSavedMachineState = n; } while (false)
 
-                                // five minutes in microseconds
-#define FIVE_MINUTES 5*60*1000000
-#define k30seconds 30*1000000
+#define MS_POP()    \
+    do { assert(kIOPM_BadMachineState != fSavedMachineState); \
+         fMachineState = fSavedMachineState; \
+         fSavedMachineState = kIOPM_BadMachineState; } while (false)
 
-/*
- There are two different kinds of power state changes.  One is initiated by a subclassed device object which has either
- decided to change power state, or its controlling driver has suggested it, or some other driver wants to use the
- idle device and has asked it to become usable.  The second kind of power state change is initiated by the power
- domain parent.  The two are handled slightly differently.
-
-There is a queue of so-called change notifications, or change notes for short.  Usually the queue is empty, and when
- it isn't, usually there is one change note in it, but since it's possible to have more than one power state change pending
- at one time, a queue is implemented.  Example:  the subclass device decides it's idle and initiates a change to a lower
- power state.  This causes interested parties to be notified, but they don't all acknowledge right away.  This causes the
- change note to sit in the queue until all the acks are received.  During this time, the device decides it isn't idle anymore and
- wants to raise power back up again.  This change can't be started, however, because the previous one isn't complete yet,
- so the second one waits in the queue.  During this time, the parent decides to lower or raise the power state of the entire
- power domain and notifies the device, and that notification goes into the queue, too, and can't be actioned until the
- others are.
+#define PM_ACTION_0(a) \
+    do { if (fPMActions.a) { \
+         (fPMActions.a)(fPMActions.target, this, &fPMActions); } \
+         } while (false)
+
+#define PM_ACTION_2(a, x, y) \
+    do { if (fPMActions.a) { \
+         (fPMActions.a)(fPMActions.target, this, &fPMActions, x, y); } \
+         } while (false)
+
+//*********************************************************************************
+// PM machine states
+//
+// Check kgmacros after modifying machine states.
+//*********************************************************************************
+
+enum {
+    kIOPM_Finished                                      = 0,
+
+    kIOPM_OurChangeTellClientsPowerDown                 = 1,
+    kIOPM_OurChangeTellPriorityClientsPowerDown         = 2,
+    kIOPM_OurChangeNotifyInterestedDriversWillChange    = 3,
+    kIOPM_OurChangeSetPowerState                        = 4,
+    kIOPM_OurChangeWaitForPowerSettle                   = 5,
+    kIOPM_OurChangeNotifyInterestedDriversDidChange     = 6,
+    kIOPM_OurChangeTellCapabilityDidChange              = 7,
+    kIOPM_OurChangeFinish                               = 8,
+
+    kIOPM_ParentChangeTellPriorityClientsPowerDown      = 10,
+    kIOPM_ParentChangeNotifyInterestedDriversWillChange = 11,
+    kIOPM_ParentChangeSetPowerState                     = 12,
+    kIOPM_ParentChangeWaitForPowerSettle                = 13,
+    kIOPM_ParentChangeNotifyInterestedDriversDidChange  = 14,
+    kIOPM_ParentChangeTellCapabilityDidChange           = 15,
+    kIOPM_ParentChangeAcknowledgePowerChange            = 16,
+
+    kIOPM_NotifyChildrenStart                           = 17,
+    kIOPM_NotifyChildrenOrdered                         = 18,
+    kIOPM_NotifyChildrenDelayed                         = 19,
+    kIOPM_SyncTellClientsPowerDown                      = 20,
+    kIOPM_SyncTellPriorityClientsPowerDown              = 21,
+    kIOPM_SyncNotifyWillChange                          = 22,
+    kIOPM_SyncNotifyDidChange                           = 23,
+    kIOPM_SyncTellCapabilityDidChange                   = 24,
+    kIOPM_SyncFinish                                    = 25,
+    kIOPM_TellCapabilityChangeDone                      = 26,
+    kIOPM_DriverThreadCallDone                          = 27,
+
+    kIOPM_BadMachineState                               = 0xFFFFFFFF
+};
 
+
+ /*
+ Power Management defines a few roles that drivers can play in their own, 
+ and other drivers', power management. We briefly define those here.
+ Many drivers implement their policy maker and power controller within the same 
+ IOService object, but that is not required. 
+== Policy Maker == 
+ * Virtual IOService PM methods a "policy maker" may implement
+    * maxCapabilityForDomainState()
+    * initialPowerStateForDomainState()
+    * powerStateForDomainState()
+    
+ * Virtual IOService PM methods a "policy maker" may CALL
+    * PMinit()
+== Power Controller ==
+ * Virtual IOService PM methods a "power controller" may implement
+    * setPowerState() 
+ * Virtual IOService PM methods a "power controller" may CALL
+    * joinPMtree()
+    * registerPowerDriver()
+=======================
+ There are two different kinds of power state changes.  
+    * One is initiated by a subclassed device object which has either decided
+      to change power state, or its controlling driver has suggested it, or
+      some other driver wants to use the idle device and has asked it to become
+      usable.  
+    * The second kind of power state change is initiated by the power domain 
+      parent.  
+ The two are handled through different code paths.
+ We maintain a queue of "change notifications," or change notes.
+    * Usually the queue is empty. 
+    * When it isn't, usually there is one change note in it 
+    * It's possible to have more than one power state change pending at one 
+        time, so a queue is implemented. 
+ Example:  
+    * The subclass device decides it's idle and initiates a change to a lower
+        power state. This causes interested parties to be notified, but they 
+        don't all acknowledge right away.  This causes the change note to sit 
+        in the queue until all the acks are received.  During this time, the 
+        device decides it isn't idle anymore and wants to raise power back up 
+        again.  This change can't be started, however, because the previous one 
+        isn't complete yet, so the second one waits in the queue.  During this 
+        time, the parent decides to lower or raise the power state of the entire
+        power domain and notifies the device, and that notification goes into 
+        the queue, too, and can't be actioned until the others are.
+ == SelfInitiated ==
  This is how a power change initiated by the subclass device is handled:
- First, all interested parties are notified of the change via their powerStateWillChangeTo method.  If they all don't
- acknowledge via return code, then we have to wait.  If they do, or when they finally all acknowledge via our
- acknowledgePowerChange method, then we can continue.  We call the controlling driver, instructing it to change to
- the new state.  Then we wait for power to settle.  If there is no settling-time, or after it has passed, we notify
- interested parties again, this time via their powerStateDidChangeTo methods.  When they have all acked, we're done.
- If we lowered power and don't need the power domain to be in its current power state, we suggest to the parent that
- it lower the power domain state.
-
- This is how a change to a lower power domain state initiated by the parent is handled:
- First, we figure out what power state we will be in when the new domain state is reached.  Then all interested parties are
- notified that we are moving to that new state.  When they have acknowledged, we call the controlling driver to assume
- that state and we wait for power to settle.  Then we acknowledge our preparedness to our parent.  When all its interested
- parties have acknowledged, it lowers power and then notifies its interested parties again.  When we get this call, we notify
- our interested parties that the power state has changed, and when they have all acknowledged, we're done.
-
- This is how a change to a higher power domain state initiated by the parent is handled:
- We figure out what power state we will be in when the new domain state is reached.  If it is different from our current
- state we acknowledge the parent.  When all the parent's interested parties have acknowledged, it raises power in the
-domain and waits for power to settle.  Then it  notifies everyone that the new state has been reached.  When we get this call,
- we call the controlling driver, instructing it  to assume the new state, and wait for power to settle.  Then we notify our interested
- parties.  When they all acknowledge  we are done.
-
- In either of the two cases above, it is possible that we will not be changing state even though the domain is.  Examples:
- A change to a lower domain state may not affect us because we are already in a low enough state, and
- We will not take advantage of a change to a higher domain state, because we have no need of the higher power.
- In such a case, there is nothing to do but acknowledge the parent.  So when the parent calls our powerDomainWillChange
- method, and we decide that we will not be changing state, we merely acknowledge the parent, via return code, and wait.
- When the parent subsequently calls powerStateDidChange, we acknowledge again via return code, and the change is complete.
-
- Power state changes are processed in a state machine, and since there are four varieties of power state changes, there are
- four major paths through the state machine:
-
- The fourth is nearly trivial.  In this path, the parent is changing the domain state, but we are not changing the device state.
- The change starts when the parent calls powerDomainWillChange.  All we do is acknowledge the parent.
-When the parent calls powerStateDidChange, we acknowledge the parent again, and we're done.
-
- The first is fairly simple.  It starts when a power domain child calls requestPowerDomainState and we decide to change power states
- to accomodate the child, or if our power-controlling driver calls changePowerStateTo, or if some other driver which is using our
- device calls makeUsable, or if a subclassed object calls changePowerStateToPriv.  These are all power changes initiated by us, not
- forced upon us by the parent.  We start by notifying interested parties.  If they all acknowledge via return code, we can go
- on to state "our_prechange_1".  Otherwise, we start the ack timer and wait for the stragglers to acknowlege by calling
- acknowledgePowerChange.  We move on to state "our_prechange_1" when all the stragglers have acknowledged,
- or when the ack timer expires on all those which didn't acknowledge.  In "our_prechange_1" we call the power-controlling
- driver to change the power state of the hardware.  If it returns saying it has done so, we go on to state "our_prechange_2".
- Otherwise, we have to wait for it, so we set the ack timer and wait.  When it calls acknowledgeSetPowerState, or when the
- ack timer expires, we go on.  In "our_prechange_2", we look in the power state array to see if there is any settle time required
- when changing from our current state to the new state.  If not, we go right away to "our_prechange_3".  Otherwise, we
- set the settle timer and wait.  When it expires, we move on.  In "our_prechange_3" state, we notify all our interested parties
- via their powerStateDidChange methods that we have finished changing power state.  If they all acknowledge via return
- code, we move on to "our_prechange_4".  Otherwise we set the ack timer and wait.  When they have all acknowledged, or
- when the ack timer has expired for those that didn't, we move on to "our_prechange_4", where we remove the used
- change note from the head of the queue and start the next one if one exists.
-
- Parent-initiated changes are more complex in the state machine.  First, power going up and power going down are handled
- differently, so they have different paths throught the state machine.  Second, we can acknowledge the parent's notification
- in two different ways, so each of the parent paths is really two.
-
- When the parent calls our powerDomainWillChange method, notifying us that it will lower power in the domain, we decide
- what state that will put our device in.  Then we embark on the state machine path "IOPMparent_down_1"
- and "IOPMparent_down_2", in which we notify interested parties of the upcoming change,  instruct our driver to make
- the change, check for settle time, and notify interested parties of the completed change.   If we get to the end of this path without
- stalling due to an interested party which didn't acknowledge via return code, due to the controlling driver not able to change
- state right away, or due to a non-zero settling time, then we return IOPMAckImplied to the parent, and we're done with the change.
- If we do stall in any of those states, we return IOPMWillAckLater to the parent and enter the parallel path "IOPMparent_down_4"
- "IOPMparent_down_5", and "IOPMparent_down_3", where we continue with the same processing, except that at the end we
- acknowledge the parent explicitly via acknowledgePowerChange, and we're done with the change.
-Then when the parent calls us at powerStateDidChange we acknowledging via return code, because we have already made
- the power change.  In any case, when we are done we remove the used change note from the head of the queue and start on the next one.
-
- The case of the parent raising power in the domain is handled similarly in that there are parallel paths, one for no-stall
- that ends in implicit acknowleging the parent, and one that has stalled at least once that ends in explicit acknowledging
- the parent.  This case is different, though in that our device changes state in the second half, after the parent calls
- powerStateDidChange rather than before, as in the power-lowering case.
-
- When the parent calls our powerDomainWillChange method, notifying us that it will raise power in the domain, we acknowledge
- via return code, because there's really nothing we can do until the power is actually raised in the domain.
- When the parent calls us at powerStateDidChange, we start by notifying our interested parties.  If they all acknowledge via return code,
- we go on to" IOPMparent_up_1" to instruct the driver to raise its power level. After that, we check for any
- necessary settling time in "IOPMparent_up_2", and we notify all interested parties that power has changed
- in "IOPMparent_up_3".  If none of these operations stall, we acknowledge the parent via return code, release
- the change note, and start the next, if there is one.  If one of them does stall, we enter the parallel path  "IOPMparent_up_0",
- "IOPMparent_up_4", "IOPMparent_up_5", and "IOPMparent_up_6", which ends with
- our explicit acknowledgement to the parent.
-
-*/
-
-
-const char priv_key[ ] = "Power Management private data";
-const char prot_key[ ] = "Power Management protected data";
+    -> First, all interested parties are notified of the change via their 
+       powerStateWillChangeTo method.  If they all don't acknowledge via return
+       code, then we have to wait.  If they do, or when they finally all
+       acknowledge via our acknowledgePowerChange method, then we can continue.  
+    -> We call the controlling driver, instructing it to change to the new state
+    -> Then we wait for power to settle. If there is no settling-time, or after 
+       it has passed, 
+    -> we notify interested parties again, this time via their 
+       powerStateDidChangeTo methods.  
+    -> When they have all acked, we're done.
+ If we lowered power and don't need the power domain to be in its current power 
+ state, we suggest to the parent that it lower the power domain state.
+ == PowerDomainDownInitiated ==
+How a change to a lower power domain state initiated by the parent is handled:
+    -> First, we figure out what power state we will be in when the new domain 
+        state is reached.  
+    -> Then all interested parties are notified that we are moving to that new 
+        state.  
+    -> When they have acknowledged, we call the controlling driver to assume
+        that state and we wait for power to settle.  
+    -> Then we acknowledge our preparedness to our parent.  When all its 
+        interested parties have acknowledged, 
+    -> it lowers power and then notifies its interested parties again.  
+    -> When we get this call, we notify our interested parties that the power 
+        state has changed, and when they have all acknowledged, we're done.
+ == PowerDomainUpInitiated ==
+How a change to a higher power domain state initiated by the parent is handled:
+    -> We figure out what power state we will be in when the new domain state is 
+        reached.  
+    -> If it is different from our current state we acknowledge the parent.  
+    -> When all the parent's interested parties have acknowledged, it raises 
+        power in the domain and waits for power to settle.  
+    -> Then it  notifies everyone that the new state has been reached.  
+    -> When we get this call, we call the controlling driver, instructing it to 
+        assume the new state, and wait for power to settle.
+    -> Then we notify our interested parties. When they all acknowledge we are 
+        done.
+ In either of the two power domain state cases above, it is possible that we 
+ will not be changing state even though the domain is. 
+ Examples:
+    * A change to a lower domain state may not affect us because we are already 
+        in a low enough state, 
+    * We will not take advantage of a change to a higher domain state, because 
+        we have no need of the higher power. In such cases, there is nothing to 
+        do but acknowledge the parent.  So when the parent calls our 
+        powerDomainWillChange method, and we decide that we will not be changing 
+        state, we merely acknowledge the parent, via return code, and wait.
+ When the parent subsequently calls powerStateDidChange, we acknowledge again 
+ via return code, and the change is complete.
+ == 4 Paths Through State Machine ==
+ Power state changes are processed in a state machine, and since there are four 
+ varieties of power state changes, there are four major paths through the state 
+ machine.
+ == 5. No Need To change ==
+ The fourth is nearly trivial.  In this path, the parent is changing the domain 
+ state, but we are not changing the device state. The change starts when the 
+ parent calls powerDomainWillChange.  All we do is acknowledge the parent. When 
+ the parent calls powerStateDidChange, we acknowledge the parent again, and 
+ we're done.
+ == 1. OurChange Down ==    XXX gvdl
+ The first is fairly simple.  It starts: 
+    * when a power domain child calls requestPowerDomainState and we decide to 
+        change power states to accomodate the child, 
+    * or if our power-controlling driver calls changePowerStateTo, 
+    * or if some other driver which is using our device calls makeUsable, 
+    * or if a subclassed object calls changePowerStateToPriv.  
+ These are all power changes initiated by us, not forced upon us by the parent.  
+ -> We start by notifying interested parties.  
+        -> If they all acknowledge via return code, we can go on to state 
+            "msSetPowerState".  
+        -> Otherwise, we start the ack timer and wait for the stragglers to 
+            acknowlege by calling acknowledgePowerChange.  
+            -> We move on to state "msSetPowerState" when all the 
+                stragglers have acknowledged, or when the ack timer expires on 
+                all those which didn't acknowledge.  
+ In "msSetPowerState" we call the power-controlling driver to change the 
+ power state of the hardware.  
+    -> If it returns saying it has done so, we go on to state 
+        "msWaitForPowerSettle".
+    -> Otherwise, we have to wait for it, so we set the ack timer and wait.  
+        -> When it calls acknowledgeSetPowerState, or when the ack timer 
+            expires, we go on.  
+ In "msWaitForPowerSettle", we look in the power state array to see if 
+ there is any settle time required when changing from our current state to the 
+ new state.  
+    -> If not, we go right away to "msNotifyInterestedDriversDidChange".  
+    -> Otherwise, we set the settle timer and wait. When it expires, we move on.  
+ In "msNotifyInterestedDriversDidChange" state, we notify all our 
+ interested parties via their powerStateDidChange methods that we have finished 
+ changing power state.  
+    -> If they all acknowledge via return code, we move on to "msFinish".  
+    -> Otherwise we set the ack timer and wait.  When they have all 
+        acknowledged, or when the ack timer has expired for those that didn't, 
+        we move on to "msFinish".
+ In "msFinish" we remove the used change note from the head of the queue 
+ and start the next one if one exists.
+
+ == 2. Parent Change Down ==
+ Start at Stage 2 of OurChange Down    XXX gvdl
+
+ == 3. Change Up ==
+ Start at Stage 4 of OurChange Down    XXX gvdl
+
+Note all parent requested changes need to acknowledge the power has changed to the parent when done.
+ */
 
+//*********************************************************************************
+// [public] PMinit
+//
+// Initialize power management.
+//*********************************************************************************
 
 void IOService::PMinit ( void )
 {
-    if ( ! initialized ) {
-
-        pm_vars =  new IOPMprot;                                       // make space for our variables
-        priv = new IOPMpriv;
-        pm_vars->init();
-        priv->init();
-        
-        setProperty(prot_key, (OSObject *) pm_vars);                   // add these to the properties
-        setProperty(priv_key, (OSObject *) priv);
-
-        priv->owner = this;
-        pm_vars->theNumberOfPowerStates = 0;                           // then initialize them
-        priv->we_are_root = false;
-        pm_vars->theControllingDriver = NULL;
-        priv->our_lock = IOLockAlloc();
-        priv->flags_lock = IOLockAlloc();
-        priv->queue_lock = IOLockAlloc();
-        pm_vars->childLock = IOLockAlloc();
-        pm_vars->parentLock = IOLockAlloc();
-        priv->interestedDrivers = new IOPMinformeeList;
-        priv->interestedDrivers->initialize();
-        priv->changeList = new IOPMchangeNoteList;
-        priv->changeList->initialize();
-        pm_vars->aggressiveness = 0;
-        for (unsigned int i = 0; i <= kMaxType; i++) {
-            pm_vars->current_aggressiveness_values[i] = 0;
-            pm_vars->current_aggressiveness_valid[i] = false;
+    if ( !initialized )
+       {
+               if ( !gIOPMInitialized )
+               {
+            gPlatform = getPlatform();
+            gIOPMWorkLoop = IOWorkLoop::workLoop();
+            if (gIOPMWorkLoop)
+            {
+                gIOPMRequestQueue = IOPMRequestQueue::create(
+                    this, OSMemberFunctionCast(IOPMRequestQueue::Action,
+                        this, &IOService::servicePMRequestQueue));
+
+                gIOPMReplyQueue = IOPMRequestQueue::create(
+                    this, OSMemberFunctionCast(IOPMRequestQueue::Action,
+                        this, &IOService::servicePMReplyQueue));
+
+                gIOPMWorkQueue = IOPMWorkQueue::create(
+                    this,
+                    OSMemberFunctionCast(IOPMWorkQueue::Action, this,
+                        &IOService::servicePMRequest),
+                    OSMemberFunctionCast(IOPMWorkQueue::Action, this,
+                        &IOService::retirePMRequest));
+
+                gIOPMFreeQueue = IOPMCompletionQueue::create(
+                    this, OSMemberFunctionCast(IOPMCompletionQueue::Action,
+                        this, &IOService::servicePMFreeQueue));
+
+                if (gIOPMWorkLoop->addEventSource(gIOPMRequestQueue) !=
+                    kIOReturnSuccess)
+                {
+                    gIOPMRequestQueue->release();
+                    gIOPMRequestQueue = 0;
+                }
+
+                if (gIOPMWorkLoop->addEventSource(gIOPMReplyQueue) !=
+                    kIOReturnSuccess)
+                {
+                    gIOPMReplyQueue->release();
+                    gIOPMReplyQueue = 0;
+                }
+
+                if (gIOPMWorkLoop->addEventSource(gIOPMWorkQueue) !=
+                    kIOReturnSuccess)
+                {
+                    gIOPMWorkQueue->release();
+                    gIOPMWorkQueue = 0;
+                }
+
+                if (gIOPMWorkLoop->addEventSource(gIOPMFreeQueue) !=
+                    kIOReturnSuccess)
+                {
+                    gIOPMFreeQueue->release();
+                    gIOPMFreeQueue = 0;
+                }
+
+                gIOPMPowerClientDevice =
+                    OSSymbol::withCStringNoCopy( "DevicePowerState" );
+
+                gIOPMPowerClientDriver =
+                    OSSymbol::withCStringNoCopy( "DriverPowerState" );
+
+                gIOPMPowerClientChildProxy =
+                    OSSymbol::withCStringNoCopy( "ChildProxyPowerState" );
+
+                gIOPMPowerClientChildren =
+                    OSSymbol::withCStringNoCopy( "ChildrenPowerState" );
+            }
+
+            if (gIOPMRequestQueue && gIOPMReplyQueue && gIOPMFreeQueue)
+                gIOPMInitialized = true;
+        }
+        if (!gIOPMInitialized)
+            return;
+
+        pwrMgt = new IOServicePM;
+        pwrMgt->init();
+        setProperty(kPwrMgtKey, pwrMgt);
+
+        queue_init(&pwrMgt->WorkChain);
+        queue_init(&pwrMgt->RequestHead);
+        queue_init(&pwrMgt->PMDriverCallQueue);
+
+        fOwner                      = this;
+        fPMLock                     = IOLockAlloc();
+        fInterestedDrivers          = new IOPMinformeeList;
+        fInterestedDrivers->initialize();
+        fDesiredPowerState          = 0;
+        fDeviceDesire               = 0;
+        fInitialPowerChange         = true;
+        fInitialSetPowerState       = true;
+        fPreviousRequestPowerFlags  = 0;
+        fDeviceOverrideEnabled      = false;
+        fMachineState               = kIOPM_Finished;
+        fSavedMachineState          = kIOPM_BadMachineState;
+        fIdleTimerMinPowerState     = 0;
+        fActivityLock               = IOLockAlloc();
+        fStrictTreeOrder            = false;
+        fActivityTicklePowerState   = -1;
+        fControllingDriver          = NULL;
+        fPowerStates                = NULL;
+        fNumberOfPowerStates        = 0;
+        fCurrentPowerState          = 0;
+        fParentsCurrentPowerFlags   = 0;
+        fMaxPowerState              = 0;
+        fName                       = getName();
+        fParentsKnowState           = false;
+        fSerialNumber               = 0;
+        fResponseArray              = NULL;
+        fNotifyClientArray          = NULL;
+        fCurrentPowerConsumption    = kIOPMUnknown;
+        fOverrideMaxPowerState      = kIOPMPowerStateMax;
+
+        if (!gIOPMRootNode && (getParentEntry(gIOPowerPlane) == getRegistryRoot()))
+        {
+            gIOPMRootNode = this;
+            fParentsKnowState = true;
+        }
+
+        fAckTimer = thread_call_allocate(
+                       &IOService::ack_timer_expired, (thread_call_param_t)this);
+        fSettleTimer = thread_call_allocate(
+                       &settle_timer_expired, (thread_call_param_t)this);
+        fIdleTimer = thread_call_allocate(
+            &idle_timer_expired, (thread_call_param_t)this);
+        fDriverCallEntry = thread_call_allocate(
+                       (thread_call_func_t) &IOService::pmDriverCallout, this);
+        assert(fDriverCallEntry);
+
+        // Check for powerChangeDone override.
+        if (OSMemberFunctionCast(void (*)(void),
+                               getResourceService(), &IOService::powerChangeDone) !=
+                         OSMemberFunctionCast(void (*)(void),
+                               this, &IOService::powerChangeDone))
+        {
+            fPCDFunctionOverride = true;
         }
-        pm_vars->myCurrentState =  0;
-        priv->imminentState = 0;
-        priv->ourDesiredPowerState = 0;
-        pm_vars->parentsCurrentPowerFlags = 0;
-        pm_vars->maxCapability = 0;
-        priv->driverDesire = 0;
-        priv->deviceDesire = 0;
-        priv->initial_change = true;
-        priv->need_to_become_usable = false;
-        priv->previousRequest = 0;
-        priv->device_overrides = false;
-        priv->machine_state = IOPMfinished;
-        pm_vars->commandQueue = NULL;
-        priv->timerEventSrc = NULL;
-        priv->clampTimerEventSrc = NULL;
-        pm_vars->PMworkloop = NULL;
-        priv->activityLock = NULL;
-        pm_vars->ourName = getName();
-        pm_vars->thePlatform = getPlatform();
-        pm_vars->parentsKnowState = false;
-        assert( pm_vars->thePlatform != 0 );
-        priv->clampOn = false;
-        pm_vars->serialNumber = 0;
-        pm_vars->responseFlags = NULL;
-        pm_vars->doNotPowerDown = true;
-        pm_vars->PMcommandGate = NULL;
-        priv->ackTimer = thread_call_allocate((thread_call_func_t)ack_timer_expired, (thread_call_param_t)this);
-        priv->settleTimer = thread_call_allocate((thread_call_func_t)settle_timer_expired, (thread_call_param_t)this);
+
+#if PM_VARS_SUPPORT
+        IOPMprot * prot = new IOPMprot;
+        if (prot)
+        {
+            prot->init();
+            prot->ourName = fName;
+            prot->thePlatform = gPlatform;
+            fPMVars = prot;
+            pm_vars = prot;
+               }
+#else
+        pm_vars = (void *) (uintptr_t) true;
+#endif
+
         initialized = true;
     }
 }
 
-
 //*********************************************************************************
-// PMfree
+// [private] PMfree
 //
-// Free up the data created in PMinit, if it exists.
+// Free the data created by PMinit. Only called from IOService::free().
 //*********************************************************************************
+
 void IOService::PMfree ( void )
 {
-    if ( priv ) {
-        if (  priv->clampTimerEventSrc != NULL ) {
-            getPMworkloop()->removeEventSource(priv->clampTimerEventSrc);
-            priv->clampTimerEventSrc->release();
-            priv->clampTimerEventSrc = NULL;
+    initialized = false;
+    pm_vars = 0;
+
+    if ( pwrMgt )
+    {
+        assert(fMachineState == kIOPM_Finished);
+        assert(fInsertInterestSet == NULL);
+        assert(fRemoveInterestSet == NULL);
+        assert(fNotifyChildArray  == NULL);
+        assert(queue_empty(&pwrMgt->RequestHead));
+        assert(queue_empty(&fPMDriverCallQueue));
+
+        if ( fSettleTimer ) {
+            thread_call_cancel(fSettleTimer);
+            thread_call_free(fSettleTimer);
+            fSettleTimer = NULL;
         }
-        if (  priv->timerEventSrc != NULL ) {
-            pm_vars->PMworkloop->removeEventSource(priv->timerEventSrc);
-            priv->timerEventSrc->release();
-            priv->timerEventSrc = NULL;
+        if ( fAckTimer ) {
+            thread_call_cancel(fAckTimer);
+            thread_call_free(fAckTimer);
+            fAckTimer = NULL;
         }
-        if ( priv->settleTimer ) {
-            thread_call_cancel(priv->settleTimer);
-            thread_call_free(priv->settleTimer);
-            priv->settleTimer = NULL;
+        if ( fIdleTimer ) {
+            thread_call_cancel(fIdleTimer);
+            thread_call_free(fIdleTimer);
+            fIdleTimer = NULL;
         }
-        if ( priv->ackTimer ) {
-            thread_call_cancel(priv->ackTimer);
-            thread_call_free(priv->ackTimer);
-            priv->ackTimer = NULL;
+        if ( fDriverCallEntry ) {
+            thread_call_free(fDriverCallEntry);
+            fDriverCallEntry = NULL;
         }
-        if ( priv->our_lock ) {
-            IOLockFree(priv->our_lock);
-            priv->our_lock = NULL;
+        if ( fPMLock ) {
+            IOLockFree(fPMLock);
+            fPMLock = NULL;
         }
-        if ( priv->flags_lock ) {
-            IOLockFree(priv->flags_lock);
-            priv->flags_lock = NULL;
+        if ( fActivityLock ) {
+            IOLockFree(fActivityLock);
+            fActivityLock = NULL;
         }
-        if ( priv->activityLock ) {
-            IOLockFree(priv->activityLock);
-            priv->activityLock = NULL;
+        if ( fInterestedDrivers ) {
+            fInterestedDrivers->release();
+            fInterestedDrivers = NULL;
         }
-        priv->interestedDrivers->release();
-        priv->changeList->release();
-        priv->release();                               // remove instance variables
-    }
-    
-    if ( pm_vars ) {
-        if ( pm_vars->commandQueue ) {
-            pm_vars->commandQueue->release();
-            pm_vars->commandQueue = NULL;
+        if (fDriverCallParamSlots && fDriverCallParamPtr) {
+            IODelete(fDriverCallParamPtr, DriverCallParam, fDriverCallParamSlots);
+            fDriverCallParamPtr = 0;
+            fDriverCallParamSlots = 0;
         }
-        if ( pm_vars->PMcommandGate ) {
-            pm_vars->PMcommandGate->release();
-            pm_vars->PMcommandGate = NULL;
+        if ( fResponseArray ) {
+            fResponseArray->release();
+            fResponseArray = NULL;
         }
-        if ( pm_vars->PMworkloop ) {
-            // The work loop object returned from getPMworkLoop() is
-            // never retained, therefore it should not be released.
-            // pm_vars->PMworkloop->release();
-            pm_vars->PMworkloop = NULL;
+        if ( fNotifyClientArray ) {
+            fNotifyClientArray->release();
+            fNotifyClientArray = NULL;
         }
-        if ( pm_vars->responseFlags ) {
-            pm_vars->responseFlags->release();
-            pm_vars->responseFlags = NULL;
+        if (fPowerStates && fNumberOfPowerStates) {
+            IODelete(fPowerStates, IOPMPSEntry, fNumberOfPowerStates);
+            fNumberOfPowerStates = 0;
+            fPowerStates = NULL;
         }
-        pm_vars->release();                            // remove instance variables
+        if (fPowerClients) {
+            fPowerClients->release();
+            fPowerClients = 0;
+        }
+
+#if PM_VARS_SUPPORT
+        if (fPMVars)
+        {
+            fPMVars->release();
+            fPMVars = 0;
+        }
+#endif
+
+        pwrMgt->release();
+        pwrMgt = 0;
     }
 }
 
+//*********************************************************************************
+// [public] joinPMtree
+//
+// A policy-maker calls its nub here when initializing, to be attached into
+// the power management hierarchy.  The default function is to call the
+// platform expert, which knows how to do it.  This method is overridden
+// by a nub subclass which may either know how to do it, or may need to
+// take other action.
+//
+// This may be the only "power management" method used in a nub,
+// meaning it may not be initialized for power management.
+//*********************************************************************************
+
+void IOService::joinPMtree ( IOService * driver )
+{
+    IOPlatformExpert *  platform;
+
+    platform = getPlatform();
+    assert(platform != 0);
+    platform->PMRegisterDevice(this, driver);
+}
+
+#ifndef __LP64__
+//*********************************************************************************
+// [deprecated] youAreRoot
+//
+// Power Managment is informing us that we are the root power domain.
+//*********************************************************************************
+
+IOReturn IOService::youAreRoot ( void )
+{
+    return IOPMNoErr;
+}
+#endif /* !__LP64__ */
 
 //*********************************************************************************
-// PMstop
+// [public] PMstop
 //
-// Disconnect the node from its parents and children in the Power Plane.
+// Immediately stop driver callouts. Schedule an async stop request to detach
+// from power plane.
 //*********************************************************************************
+
 void IOService::PMstop ( void )
 {
-    OSIterator *       iter;
-    OSObject *         next;
+    IOPMRequest * request;
+
+    if (!initialized)
+        return;
+
+    PM_LOCK();
+
+    if (fLockedFlags.PMStop)
+    {
+        PM_LOG2("%s: PMstop() already stopped\n", fName);
+        PM_UNLOCK();
+        return;
+    }
+
+    // Inhibit future driver calls.
+    fLockedFlags.PMStop = true;
+
+    // Wait for all prior driver calls to finish.
+    waitForPMDriverCall();
+
+    PM_UNLOCK();
+
+    // The rest of the work is performed async.
+    request = acquirePMRequest( this, kIOPMRequestTypePMStop );
+    if (request)
+    {
+        PM_LOG2("%s: %p PMstop\n", getName(), this);
+        submitPMRequest( request );
+    }
+}
+
+//*********************************************************************************
+// [private] handlePMstop
+//
+// Disconnect the node from all parents and children in the power plane.
+//*********************************************************************************
+
+void IOService::handlePMstop ( IOPMRequest * request )
+{
+    OSIterator *        iter;
+    OSObject *                 next;
     IOPowerConnection *        connection;
-    IOService *                theChild;
-    IOService *                theParent;
+    IOService *                        theChild;
+    IOService *                        theParent;
 
-    removeProperty(prot_key);                  // remove the properties
-    removeProperty(priv_key);
-    
-    iter = getParentIterator(gIOPowerPlane);   // detach parents
+       PM_ASSERT_IN_GATE();
+       PM_LOG2("%s: %p %s start\n", getName(), this, __FUNCTION__);
+
+    // remove the property
+    removeProperty(kPwrMgtKey);                        
 
-    if ( iter ) {
-        while ( (next = iter->getNextObject()) ) {
-            if ( (connection = OSDynamicCast(IOPowerConnection,next)) ) {
+    // detach parents
+    iter = getParentIterator(gIOPowerPlane);
+    if ( iter )
+    {
+        while ( (next = iter->getNextObject()) )
+        {
+            if ( (connection = OSDynamicCast(IOPowerConnection, next)) )
+            {
                 theParent = (IOService *)connection->copyParentEntry(gIOPowerPlane);
-                if ( theParent ) {
+                if ( theParent )
+                {
                     theParent->removePowerChild(connection);
                     theParent->release();
                 }
@@ -375,21 +768,30 @@ void IOService::PMstop ( void )
         }
         iter->release();
     }
-    detachAbove( gIOPowerPlane );              // detach IOConnections   
-    
-    pm_vars->parentsKnowState = false;         // no more power state changes
 
-    iter = getChildIterator(gIOPowerPlane);    // detach children
+    // detach IOConnections
+    detachAbove( gIOPowerPlane );
+    
+    // no more power state changes
+    fParentsKnowState = false;
 
-    if ( iter ) {
-        while ( (next = iter->getNextObject()) ) {
-            if ( (connection = OSDynamicCast(IOPowerConnection,next)) ) {
+    // detach children
+    iter = getChildIterator(gIOPowerPlane);
+    if ( iter )
+    {
+        while ( (next = iter->getNextObject()) )
+        {
+            if ( (connection = OSDynamicCast(IOPowerConnection, next)) )
+            {
                 theChild = ((IOService *)(connection->copyChildEntry(gIOPowerPlane)));
-                if ( theChild ) {
-                    connection->detachFromChild(theChild,gIOPowerPlane);       // detach nub from child
+                if ( theChild )
+                {
+                    // detach nub from child
+                    connection->detachFromChild(theChild, gIOPowerPlane);
                     theChild->release();
                 }
-                detachFromChild(connection,gIOPowerPlane);                     // detach us from nub
+                // detach us from nub
+                detachFromChild(connection, gIOPowerPlane);
             }
         }
         iter->release();
@@ -403,319 +805,506 @@ void IOService::PMstop ( void )
     // the object will be holding an extra retain on itself, and cannot
     // be freed.
 
-    if ( priv && priv->interestedDrivers )
+    if ( fInterestedDrivers )
     {
-        IOPMinformee * informee;
+        IOPMinformeeList *     list = fInterestedDrivers;
+        IOPMinformee *         item;
 
-        while (( informee = priv->interestedDrivers->firstInList() ))
-            deRegisterInterestedDriver( informee->whatObject );
+        PM_LOCK();
+        while ((item = list->firstInList()))
+        {
+            list->removeFromList(item->whatObject);
+        }
+        PM_UNLOCK();
     }
-}
 
+    // Tell idleTimerExpired() to ignore idle timer.
+    fIdleTimerPeriod = 0;
+    if (fIdleTimer && thread_call_cancel(fIdleTimer))
+        release();
+
+    PM_LOG2("%s: %p %s done\n", getName(), this, __FUNCTION__);
+}
 
 //*********************************************************************************
-// joinPMtree
-//
-// A policy-maker calls its nub here when initializing, to be attached into
-// the power management hierarchy.  The default function is to call the
-// platform expert, which knows how to do it.  This method is overridden
-// by a nub subclass which may either know how to do it, or may need
-// to take other action.
+// [public] addPowerChild
 //
-// This may be the only "power management" method used in a nub,
-// meaning it may not be initialized for power management.
+// Power Management is informing us who our children are.
 //*********************************************************************************
-void IOService::joinPMtree ( IOService * driver )
+
+IOReturn IOService::addPowerChild ( IOService * child )
 {
-    IOPlatformExpert * thePlatform;
+       IOPowerConnection *     connection  = 0;
+       IOPMRequest *           requests[3] = {0, 0, 0};
+    OSIterator *               iter;
+       bool                            ok = true;
+
+       if (!child)
+               return kIOReturnBadArgument;
+
+    if (!initialized || !child->initialized)
+               return IOPMNotYetInitialized;
+
+    OUR_PMLog( kPMLogAddChild, (uintptr_t) child, 0 );
+
+       do {
+               // Is this child already one of our children?
+
+               iter = child->getParentIterator( gIOPowerPlane );
+               if ( iter )
+               {
+                       IORegistryEntry *       entry;
+                       OSObject *                      next;
+
+                       while ((next = iter->getNextObject()))
+                       {
+                               if ((entry = OSDynamicCast(IORegistryEntry, next)) &&
+                                       isChild(entry, gIOPowerPlane))
+                               {
+                                       ok = false;
+                                       break;
+                               }                       
+                       }
+                       iter->release();
+               }
+               if (!ok)
+               {
+                       PM_LOG("%s: %s (%p) is already a child\n",
+                               getName(), child->getName(), child);
+                       break;
+               }
+
+               // Add the child to the power plane immediately, but the
+               // joining connection is marked as not ready.
+               // We want the child to appear in the power plane before
+               // returning to the caller, but don't want the caller to
+               // block on the PM work loop.
+
+               connection = new IOPowerConnection;
+               if (!connection)
+                       break;
+
+               // Create a chain of PM requests to perform the bottom-half
+               // work from the PM work loop.
+
+               requests[0] = acquirePMRequest(
+                                       /* target */ this,
+                                       /* type */   kIOPMRequestTypeAddPowerChild1 );
+
+               requests[1] = acquirePMRequest(
+                                       /* target */ child,
+                                       /* type */   kIOPMRequestTypeAddPowerChild2 );
+
+               requests[2] = acquirePMRequest(
+                                       /* target */ this,
+                                       /* type */   kIOPMRequestTypeAddPowerChild3 );
+
+               if (!requests[0] || !requests[1] || !requests[2])
+                       break;
+
+               requests[0]->attachNextRequest( requests[1] );
+               requests[1]->attachNextRequest( requests[2] );
+
+               connection->init();
+               connection->start(this);
+               connection->setAwaitingAck(false);
+               connection->setReadyFlag(false);
+
+               attachToChild( connection, gIOPowerPlane );
+               connection->attachToChild( child, gIOPowerPlane );
+
+               // connection needs to be released
+               requests[0]->fArg0 = connection;
+               requests[1]->fArg0 = connection;
+               requests[2]->fArg0 = connection;
+
+               submitPMRequest( requests, 3 );
+               return kIOReturnSuccess;
+       }
+       while (false);
 
-    thePlatform = getPlatform();
-    assert(thePlatform != 0 );
-    thePlatform->PMRegisterDevice(this,driver);
-}
+       if (connection)  connection->release();
+       if (requests[0]) releasePMRequest(requests[0]);
+       if (requests[1]) releasePMRequest(requests[1]);
+       if (requests[2]) releasePMRequest(requests[2]);
 
+       // Silent failure, to prevent platform drivers from adding the child
+       // to the root domain.
 
-//*********************************************************************************
-// youAreRoot
-//
-// Power Managment is informing us that we are the root power domain.
-// The only difference between us and any other power domain is that
-// we have no parent and therefore never call it.
-//*********************************************************************************
-IOReturn IOService::youAreRoot ( void )
-{    
-    priv-> we_are_root = true;
-    pm_vars->parentsKnowState = true;
-    attachToParent( getRegistryRoot(),gIOPowerPlane );
-    
-    return IOPMNoErr;
+       return kIOReturnSuccess;
 }
 
-
 //*********************************************************************************
-// setPowerParent
+// [private] addPowerChild1
 //
-// Power Management is informing us who our parent is.
-// If we have a controlling driver, find out, given our newly-informed
-// power domain state, what state it would be in, and then tell it
-// to assume that state.
+// Step 1/3 of adding a power child. Called on the power parent.
 //*********************************************************************************
-IOReturn IOService::setPowerParent ( IOPowerConnection * theParent, bool stateKnown, IOPMPowerFlags currentState )
+
+void IOService::addPowerChild1 ( IOPMRequest * request )
 {
-    OSIterator *                       iter;
-    OSObject *                 next;
-    IOPowerConnection *        connection;
-    unsigned long              tempDesire;
+       unsigned long tempDesire = 0;
 
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogSetParent,stateKnown,currentState);
-    
-    IOLockLock(pm_vars->parentLock);
-    
-    if ( stateKnown && ((pm_vars->PMworkloop == NULL) || (pm_vars->PMcommandGate == NULL)) ) {
-        getPMworkloop();                                               // we have a path to the root
-        if ( pm_vars->PMworkloop != NULL ) {                           // find out the workloop
-            if ( pm_vars->PMcommandGate == NULL ) {                    // and make our command gate
-                pm_vars->PMcommandGate = IOCommandGate::commandGate((OSObject *)this);
-                if ( pm_vars->PMcommandGate != NULL ) {
-                    pm_vars->PMworkloop->addEventSource(pm_vars->PMcommandGate);
-                }
-            }
-        }
-    }
-    
-    IOLockUnlock(pm_vars->parentLock);
+       // Make us temporary usable before adding the child.
 
-    theParent->setParentCurrentPowerFlags(currentState);       // set our connection data
-    theParent->setParentKnowsState(stateKnown);
+       PM_ASSERT_IN_GATE();
+    OUR_PMLog( kPMLogMakeUsable, kPMLogMakeUsable, 0 );
 
-    pm_vars->parentsKnowState = true;                          // combine parent knowledge
-    pm_vars->parentsCurrentPowerFlags = 0;
-    
-    iter = getParentIterator(gIOPowerPlane);
+       if (fControllingDriver && inPlane(gIOPowerPlane) && fParentsKnowState)
+       {
+               tempDesire = fNumberOfPowerStates - 1;
+       }
 
-    if ( iter ) {
-        while ( (next = iter->getNextObject()) ) {
-            if ( (connection = OSDynamicCast(IOPowerConnection,next)) ) {
-                pm_vars->parentsKnowState &= connection->parentKnowsState();
-                pm_vars->parentsCurrentPowerFlags |= connection->parentCurrentPowerFlags();
-            }
-        }
-        iter->release();
-    }
-    
-    if ( (pm_vars->theControllingDriver != NULL) &&
-         (pm_vars->parentsKnowState) ) {
-        pm_vars->maxCapability = pm_vars->theControllingDriver->maxCapabilityForDomainState(pm_vars->parentsCurrentPowerFlags);
-        tempDesire = priv->deviceDesire;                       // initially change into the state we are already in
-        priv->deviceDesire = pm_vars->theControllingDriver->initialPowerStateForDomainState(pm_vars->parentsCurrentPowerFlags);
-        computeDesiredState();
-        priv->previousRequest = 0xffffffff;
-        changeState();
-        priv->deviceDesire = tempDesire;                       // put this back like before
-    }
-    
-   return IOPMNoErr;
+       if (tempDesire && (IS_PM_ROOT || (fMaxPowerState >= tempDesire)))
+       {
+               adjustPowerState(tempDesire);
+       }
 }
 
-
 //*********************************************************************************
-// addPowerChild
+// [private] addPowerChild2
 //
-// Power Management is informing us who our children are.
+// Step 2/3 of adding a power child. Called on the joining child.
+// Execution blocked behind addPowerChild1.
 //*********************************************************************************
-IOReturn IOService::addPowerChild ( IOService * theChild )
+
+void IOService::addPowerChild2 ( IOPMRequest * request )
 {
-    IOPowerConnection *        connection;
-    unsigned int        i;
+       IOPowerConnection * connection = (IOPowerConnection *) request->fArg0;
+       IOService *         parent;
+       IOPMPowerFlags          powerFlags;
+       bool                            knowsState;
+       unsigned long           powerState;
+       unsigned long           tempDesire;
+
+       PM_ASSERT_IN_GATE();
+       parent = (IOService *) connection->getParentEntry(gIOPowerPlane);
+
+       if (!parent || !inPlane(gIOPowerPlane))
+       {
+               PM_LOG("%s: addPowerChild2 not in power plane\n", getName());
+               return;
+       }
 
-    if ( ! initialized ) {
-        return IOPMNotYetInitialized;  // we're not a power-managed IOService
-    }
+       // Parent will be waiting for us to complete this stage.
+       // It is safe to directly access parent's vars.
 
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogAddChild,0,0);
+       knowsState = (parent->fPowerStates) && (parent->fParentsKnowState);
+       powerState = parent->fCurrentPowerState;
 
-    connection = new IOPowerConnection;                        // make a nub
+       if (knowsState)
+               powerFlags = parent->fPowerStates[powerState].outputPowerFlags;
+       else
+               powerFlags = 0;
 
-    connection->init();
-    connection->start(this);
-    connection->setAwaitingAck(false);
+       // Set our power parent.
 
-    attachToChild( connection,gIOPowerPlane );                 // connect it up
-    connection->attachToChild( theChild,gIOPowerPlane );
-    connection->release();
-    
-    if ( (pm_vars->theControllingDriver == NULL) ||            // tell it the current state of the power domain
-         ! (inPlane(gIOPowerPlane)) ||
-       ! (pm_vars->parentsKnowState) ) {
-        theChild->setPowerParent(connection,false,0);
-        if ( inPlane(gIOPowerPlane) ) {
-            for (i = 0; i <= kMaxType; i++) {
-                if ( pm_vars->current_aggressiveness_valid[i] ) {
-                    theChild->setAggressiveness (i, pm_vars->current_aggressiveness_values[i]);
-                }
-            }
-        }
-    }
-    else {
-        theChild->setPowerParent(connection,true,pm_vars->thePowerStates[pm_vars->myCurrentState].outputPowerCharacter);
-        for (i = 0; i <= kMaxType; i++) {
-            if ( pm_vars->current_aggressiveness_valid[i] ) {
-                theChild->setAggressiveness (i, pm_vars->current_aggressiveness_values[i]);
-            }
-        }
-        add_child_to_active_change(connection);                                                        // catch it up if change is in progress
+    OUR_PMLog(kPMLogSetParent, knowsState, powerFlags);
+
+       setParentInfo( powerFlags, connection, knowsState );
+
+       connection->setReadyFlag(true);
+
+    if ( fControllingDriver && fParentsKnowState )
+    {
+        fMaxPowerState = fControllingDriver->maxCapabilityForDomainState(fParentsCurrentPowerFlags);
+        // initially change into the state we are already in
+        tempDesire = fControllingDriver->initialPowerStateForDomainState(fParentsCurrentPowerFlags);
+        fPreviousRequestPowerFlags = (IOPMPowerFlags)(-1);
+        adjustPowerState(tempDesire);
     }
-    
-    return IOPMNoErr;
+
+    getPMRootDomain()->tagPowerPlaneService(this, &fPMActions);
+}
+
+//*********************************************************************************
+// [private] addPowerChild3
+//
+// Step 3/3 of adding a power child. Called on the parent.
+// Execution blocked behind addPowerChild2.
+//*********************************************************************************
+
+void IOService::addPowerChild3 ( IOPMRequest * request )
+{
+       IOPowerConnection * connection = (IOPowerConnection *) request->fArg0;
+       IOService *         child;
+    IOPMrootDomain *    rootDomain = getPMRootDomain();
+
+       PM_ASSERT_IN_GATE();
+       child = (IOService *) connection->getChildEntry(gIOPowerPlane);
+
+       if (child && inPlane(gIOPowerPlane))
+       {
+               if (child->getProperty("IOPMStrictTreeOrder"))
+               {
+                       PM_LOG1("%s: strict PM order enforced\n", getName());
+                       fStrictTreeOrder = true;
+               }
+
+        if (rootDomain)
+            rootDomain->joinAggressiveness( child );
+       }
+       else
+       {
+               PM_LOG("%s: addPowerChild3 not in power plane\n", getName());
+       }
+
+       connection->release();
 }
 
+#ifndef __LP64__
+//*********************************************************************************
+// [deprecated] setPowerParent
+//
+// Power Management is informing us who our parent is.
+// If we have a controlling driver, find out, given our newly-informed
+// power domain state, what state it would be in, and then tell it
+// to assume that state.
+//*********************************************************************************
+
+IOReturn IOService::setPowerParent (
+       IOPowerConnection * theParent, bool stateKnown, IOPMPowerFlags powerFlags )
+{
+       return kIOReturnUnsupported;
+}
+#endif /* !__LP64__ */
 
 //*********************************************************************************
-// removePowerChild
+// [public] removePowerChild
 //
+// Called on a parent whose child is being removed by PMstop().
 //*********************************************************************************
+
 IOReturn IOService::removePowerChild ( IOPowerConnection * theNub )
 {
-    IORegistryEntry * theChild;
+    IORegistryEntry *  theChild;
 
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogRemoveChild,0,0);
+       PM_ASSERT_IN_GATE();
+    OUR_PMLog( kPMLogRemoveChild, 0, 0 );
 
     theNub->retain();
-    
-    theChild = theNub->copyChildEntry(gIOPowerPlane);                  // detach nub from child
-    if ( theChild ) {
+
+    // detach nub from child
+    theChild = theNub->copyChildEntry(gIOPowerPlane);                  
+    if ( theChild )
+    {
         theNub->detachFromChild(theChild, gIOPowerPlane);
         theChild->release();
     }
-    detachFromChild(theNub,gIOPowerPlane);                             // detach from the nub
-    
-    if ( theNub->getAwaitingAck() ) {                                  // are we awaiting an ack from this child?
-        theNub->setAwaitingAck(false);                                 // yes, pretend we got one
-        if ( acquire_lock() ) {
-            if (priv->head_note_pendingAcks != 0 ) {
-                priv->head_note_pendingAcks -= 1;                      // that's one fewer ack to worry about
-                if ( priv->head_note_pendingAcks == 0 ) {              // is that the last?
-                    stop_ack_timer();                                  // yes, stop the timer
-                    IOUnlock(priv->our_lock);
-                    all_acked();                                       // and now we can continue our power change
-                }
-                else {
-                    IOUnlock(priv->our_lock);
-                }
-            }
-            else {
-                IOUnlock(priv->our_lock);
-            }
-        }
-    }
-    
-    theNub->release();
+    // detach from the nub
+    detachFromChild(theNub, gIOPowerPlane);
+
+    // Are we awaiting an ack from this child?
+    if ( theNub->getAwaitingAck() )
+       {
+               // yes, pretend we got one
+               theNub->setAwaitingAck(false);
+               if (fHeadNotePendingAcks != 0 )
+               {
+                       // that's one fewer ack to worry about
+                       fHeadNotePendingAcks--;
+
+                       // is that the last?
+                       if ( fHeadNotePendingAcks == 0 )
+                       {
+                               stop_ack_timer();
+
+                               // Request unblocked, work queue
+                               // should re-scan all busy requests.
+                               gIOPMWorkQueue->incrementProducerCount();
+                       }
+               }
+       }
 
-    if ( (pm_vars->theControllingDriver == NULL) ||    // if not fully initialized
-         ! (inPlane(gIOPowerPlane)) ||
-       ! (pm_vars->parentsKnowState) ) {
-        return IOPMNoErr;                              // we can do no more
-    }
+       theNub->release();
 
-    computeDesiredState();                             // this may be different now
-    changeState();                                     // change state if we can now tolerate lower power
+       // A child has gone away, re-scan children desires and clamp bits.
+    // The fPendingAdjustPowerRequest helps to reduce redundant parent work. 
+
+       if (!fAdjustPowerScheduled)
+       {
+               IOPMRequest * request;
+               request = acquirePMRequest( this, kIOPMRequestTypeAdjustPowerState );
+               if (request)
+               {
+                       submitPMRequest( request );
+                       fAdjustPowerScheduled = true;
+               }
+       }
 
     return IOPMNoErr;
 }
 
-
 //*********************************************************************************
-// registerPowerDriver
+// [public] registerPowerDriver
 //
 // A driver has called us volunteering to control power to our device.
-// If the power state array it provides is richer than the one we already
-// know about (supplied by an earlier volunteer), then accept the offer.
-// Notify all interested parties of our power state, which we now know.
-//*********************************************************************************
-
-IOReturn IOService::registerPowerDriver ( IOService * controllingDriver, IOPMPowerState* powerStates, unsigned long numberOfStates  )
-{
-    unsigned long i;
-    unsigned long tempDesire;
-
-    if ( (numberOfStates > pm_vars->theNumberOfPowerStates) && (numberOfStates > 1) ) {
-        if (  priv->changeList->currentChange() == -1 ) {
-            if ( controllingDriver != NULL ) {
-                if ( numberOfStates <= IOPMMaxPowerStates ) {
-                    switch ( powerStates[0].version  ) {
-                        case 1:
-                            pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogControllingDriver,
-                                                                    (unsigned long)numberOfStates, (unsigned long)powerStates[0].version);
-                            for ( i = 0; i < numberOfStates; i++ ) {
-                                pm_vars->thePowerStates[i] = powerStates[i];
-                            }
-                                break;
-                        case 2:
-                            pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogControllingDriver,
-                                                                    (unsigned long) numberOfStates,(unsigned long) powerStates[0].version);
-                            for ( i = 0; i < numberOfStates; i++ ) {
-                                pm_vars->thePowerStates[i].version = powerStates[i].version;
-                                pm_vars->thePowerStates[i].capabilityFlags = powerStates[i].capabilityFlags;
-                                pm_vars->thePowerStates[i].outputPowerCharacter = powerStates[i].outputPowerCharacter;
-                                pm_vars->thePowerStates[i].inputPowerRequirement = powerStates[i].inputPowerRequirement;
-                                pm_vars->thePowerStates[i].staticPower = powerStates[i].staticPower;
-                                pm_vars->thePowerStates[i].unbudgetedPower = powerStates[i].unbudgetedPower;
-                                pm_vars->thePowerStates[i].powerToAttain = powerStates[i].powerToAttain;
-                                pm_vars->thePowerStates[i].timeToAttain = powerStates[i].timeToAttain;
-                                pm_vars->thePowerStates[i].settleUpTime = powerStates[i].settleUpTime;
-                                pm_vars->thePowerStates[i].timeToLower = powerStates[i].timeToLower;
-                                pm_vars->thePowerStates[i].settleDownTime = powerStates[i].settleDownTime;
-                                pm_vars->thePowerStates[i].powerDomainBudget = powerStates[i].powerDomainBudget;
-                            }
-                                break;
-                        default:
-                            pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogControllingDriverErr1,
-                                                                    (unsigned long)powerStates[0].version,0);
-                            return IOPMNoErr;
-                    }
+//*********************************************************************************
 
-                    pm_vars->myCharacterFlags = 0;     // make a mask of all the character bits we know about
-                    for ( i = 0; i < numberOfStates; i++ ) {
-                        pm_vars->myCharacterFlags |= pm_vars->thePowerStates[i].outputPowerCharacter;
-                    }
-                    
-                   pm_vars->theNumberOfPowerStates = numberOfStates;
-                    pm_vars->theControllingDriver = controllingDriver;
-                    if ( priv->interestedDrivers->findItem(controllingDriver) == NULL ) {      // register it as interested
-                        registerInterestedDriver (controllingDriver );                         // unless already done
-                    }
-                    if ( priv->need_to_become_usable ) {
-                        priv->need_to_become_usable = false;
-                        priv->deviceDesire = pm_vars->theNumberOfPowerStates - 1;
-                    }
+IOReturn IOService::registerPowerDriver (
+       IOService *                     powerDriver,
+       IOPMPowerState *        powerStates,
+       unsigned long           numberOfStates )
+{
+       IOPMRequest *   request;
+       IOPMPSEntry *   powerStatesCopy = 0;
 
-                    if ( inPlane(gIOPowerPlane) &&
-                         (pm_vars->parentsKnowState) ) {
-                        pm_vars->maxCapability = pm_vars->theControllingDriver->maxCapabilityForDomainState(pm_vars->parentsCurrentPowerFlags);
-                        tempDesire = priv->deviceDesire;                       // initially change into the state we are already in
-                        priv->deviceDesire = pm_vars->theControllingDriver->initialPowerStateForDomainState(pm_vars->parentsCurrentPowerFlags);
-                        computeDesiredState();
-                        changeState();
-                        priv->deviceDesire = tempDesire;                       // put this back like before
-                    }
-                }
-                else {
-                    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogControllingDriverErr2,(unsigned long)numberOfStates,0);
-                }
-            }
-            else {
-                pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogControllingDriverErr4,0,0);
-            }
-        }
-    }
-    else {
-        pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogControllingDriverErr5,(unsigned long)numberOfStates,0);
-    }
-    return IOPMNoErr;
-}
+    if (!initialized)
+               return IOPMNotYetInitialized;
+
+       // Validate arguments.
+       if (!powerStates || (numberOfStates < 2))
+       {
+               OUR_PMLog(kPMLogControllingDriverErr5, numberOfStates, 0);
+               return kIOReturnBadArgument;
+       }
+
+       if (!powerDriver || !powerDriver->initialized)
+       {
+               OUR_PMLog(kPMLogControllingDriverErr4, 0, 0);
+               return kIOReturnBadArgument;
+       }
+
+       if (powerStates[0].version != kIOPMPowerStateVersion1)
+       {
+               OUR_PMLog(kPMLogControllingDriverErr1, powerStates[0].version, 0);
+               return kIOReturnBadArgument;
+       }
+
+       do {
+               // Make a copy of the supplied power state array.
+               powerStatesCopy = IONew(IOPMPSEntry, numberOfStates);
+               if (!powerStatesCopy)
+                       break;
+
+        for (uint32_t i = 0; i < numberOfStates; i++)
+        {
+            powerStatesCopy[i].capabilityFlags  = powerStates[i].capabilityFlags;
+            powerStatesCopy[i].outputPowerFlags = powerStates[i].outputPowerCharacter;
+            powerStatesCopy[i].inputPowerFlags  = powerStates[i].inputPowerRequirement;
+            powerStatesCopy[i].staticPower      = powerStates[i].staticPower;
+            powerStatesCopy[i].settleUpTime     = powerStates[i].settleUpTime;
+            powerStatesCopy[i].settleDownTime   = powerStates[i].settleDownTime;
+        }
+
+               request = acquirePMRequest( this, kIOPMRequestTypeRegisterPowerDriver );
+               if (!request)
+                       break;
+
+               powerDriver->retain();
+               request->fArg0 = (void *) powerDriver;
+               request->fArg1 = (void *) powerStatesCopy;
+               request->fArg2 = (void *) numberOfStates;
+
+               submitPMRequest( request );
+               return kIOReturnSuccess;
+       }
+       while (false);
+
+       if (powerStatesCopy)
+               IODelete(powerStatesCopy, IOPMPSEntry, numberOfStates);
+       return kIOReturnNoMemory;
+}
+
+//*********************************************************************************
+// [private] handleRegisterPowerDriver
+//*********************************************************************************
+
+void IOService::handleRegisterPowerDriver ( IOPMRequest * request )
+{
+       IOService *     powerDriver    = (IOService *)   request->fArg0;
+       IOPMPSEntry *   powerStates    = (IOPMPSEntry *) request->fArg1;
+       unsigned long   numberOfStates = (unsigned long) request->fArg2;
+    unsigned long   i;
+       IOService *     root;
+       OSIterator *    iter;
+
+       PM_ASSERT_IN_GATE();
+       assert(powerStates);
+       assert(powerDriver);
+       assert(numberOfStates > 1);
+
+    if ( !fNumberOfPowerStates )
+    {
+               OUR_PMLog(kPMLogControllingDriver,
+                       (unsigned long) numberOfStates,
+                       (unsigned long) kIOPMPowerStateVersion1);
+
+        fPowerStates            = powerStates;
+               fNumberOfPowerStates    = numberOfStates;
+               fControllingDriver      = powerDriver;
+        fCurrentCapabilityFlags = fPowerStates[0].capabilityFlags;
+
+               // make a mask of all the character bits we know about
+               fOutputPowerCharacterFlags = 0;
+               for ( i = 0; i < numberOfStates; i++ ) {
+                       fOutputPowerCharacterFlags |= fPowerStates[i].outputPowerFlags;
+               }
+
+               // Register powerDriver as interested, unless already done.
+               // We don't want to register the default implementation since
+               // it does nothing. One ramification of not always registering
+               // is the one fewer retain count held.
+
+               root = getPlatform()->getProvider();
+               assert(root);
+               if (!root ||
+                       ((OSMemberFunctionCast(void (*)(void),
+                               root, &IOService::powerStateDidChangeTo)) !=
+                       ((OSMemberFunctionCast(void (*)(void),
+                               this, &IOService::powerStateDidChangeTo)))) ||
+                       ((OSMemberFunctionCast(void (*)(void),
+                               root, &IOService::powerStateWillChangeTo)) !=
+                       ((OSMemberFunctionCast(void (*)(void),
+                               this, &IOService::powerStateWillChangeTo)))))
+               {               
+                       if (fInterestedDrivers->findItem(powerDriver) == NULL)
+                       {
+                               PM_LOCK();
+                               fInterestedDrivers->appendNewInformee(powerDriver);
+                               PM_UNLOCK();
+                       }
+               }
+
+               // Examine all existing power clients and perform limit check.
+
+        if (fPowerClients)
+        {
+            iter = OSCollectionIterator::withCollection(fPowerClients);
+            if (iter)
+            {
+                const OSSymbol * client;
+                while ((client = (const OSSymbol *) iter->getNextObject()))
+                {
+                    uint32_t powerState = getPowerStateForClient(client);
+                    if (powerState >= numberOfStates)
+                    {
+                        updatePowerClient(client, numberOfStates - 1);
+                    }
+                }
+                iter->release();
+            }
+        }
+
+               if ( inPlane(gIOPowerPlane) && fParentsKnowState )
+               {
+                       unsigned long tempDesire;
+                       fMaxPowerState = fControllingDriver->maxCapabilityForDomainState(fParentsCurrentPowerFlags);
+                       // initially change into the state we are already in
+                       tempDesire = fControllingDriver->initialPowerStateForDomainState(fParentsCurrentPowerFlags);
+                       adjustPowerState(tempDesire);
+               }
+       }
+       else
+       {
+               OUR_PMLog(kPMLogControllingDriverErr2, numberOfStates, 0);
+        IODelete(powerStates, IOPMPSEntry, numberOfStates);
+       }
+
+       powerDriver->release();
+}
 
 //*********************************************************************************
-// registerInterestedDriver
+// [public] registerInterestedDriver
 //
 // Add the caller to our list of interested drivers and return our current
 // power state.  If we don't have a power-controlling driver yet, we will
@@ -723,61 +1312,140 @@ IOReturn IOService::registerPowerDriver ( IOService * controllingDriver, IOPMPow
 // out what the current power state of the device is.
 //*********************************************************************************
 
-IOPMPowerFlags IOService::registerInterestedDriver ( IOService * theDriver )
+IOPMPowerFlags IOService::registerInterestedDriver ( IOService * driver )
 {
-    IOPMinformee * newInformee;
-    IOPMPowerFlags futureCapability;
+    IOPMRequest *      request;
+    bool                       signal;
 
-    if (theDriver == NULL ) {
+    if (!driver || !initialized || !fInterestedDrivers)
         return 0;
+
+    PM_LOCK();
+    signal = (!fInsertInterestSet && !fRemoveInterestSet);
+    if (fInsertInterestSet == NULL)
+        fInsertInterestSet = OSSet::withCapacity(4);
+    if (fInsertInterestSet)
+    {
+        fInsertInterestSet->setObject(driver);
+        if (fRemoveInterestSet)
+            fRemoveInterestSet->removeObject(driver);
+    }
+    PM_UNLOCK();
+
+    if (signal)
+    {
+        request = acquirePMRequest( this, kIOPMRequestTypeInterestChanged );
+        if (request)
+            submitPMRequest( request );
     }
 
-    newInformee = new IOPMinformee;                            // make new driver node
-    newInformee->initialize(theDriver);
-    priv->interestedDrivers->addToList(newInformee);                   // add it to list of drivers
+    // This return value cannot be trusted, but return a value
+    // for those clients that care.
+
+    OUR_PMLog(kPMLogInterestedDriver, kIOPMDeviceUsable, 2);
+    return kIOPMDeviceUsable;  
+}
+
+//*********************************************************************************
+// [public] deRegisterInterestedDriver
+//*********************************************************************************
 
-    if ( (pm_vars->theControllingDriver == NULL) ||
-         ! (inPlane(gIOPowerPlane)) ||
-       ! (pm_vars->parentsKnowState) ) {
-        pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogInterestedDriver,IOPMNotPowerManaged,0);
-        return IOPMNotPowerManaged;                                    // can't tell it a state yet
+IOReturn IOService::deRegisterInterestedDriver ( IOService * driver )
+{
+    IOPMinformeeList * list;
+    IOPMinformee *             item;
+    IOPMRequest *       request;
+    bool                signal;
+
+    if (!driver)
+        return kIOReturnBadArgument;
+    if (!initialized || !fInterestedDrivers)
+        return IOPMNotPowerManaged;
+
+    PM_LOCK();
+    signal = (!fRemoveInterestSet && !fInsertInterestSet);
+    if (fRemoveInterestSet == NULL)
+        fRemoveInterestSet = OSSet::withCapacity(4);
+    if (fRemoveInterestSet)
+    {
+        fRemoveInterestSet->setObject(driver);
+        if (fInsertInterestSet)
+            fInsertInterestSet->removeObject(driver);
+
+        list = fInterestedDrivers;
+        item = list->findItem(driver);
+        if (item && item->active)
+        {
+            item->active = false;
+            waitForPMDriverCall( driver );
+        }
     }
+    PM_UNLOCK();
 
-    switch (priv->machine_state) {                                     // can we notify new driver of a change in progress?
-        case IOPMour_prechange_1:
-        case IOPMour_prechange_4:
-        case IOPMparent_down_4:
-        case IOPMparent_down_6:
-        case IOPMparent_up_0:
-        case IOPMparent_up_6:
-            futureCapability = priv->head_note_capabilityFlags;                        // yes, remember what we tell it
-            pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogInterestedDriver,(unsigned long)futureCapability,1);
-            add_driver_to_active_change(newInformee);                          // notify it
-            return futureCapability;                                           // and return the same thing
+    if (signal)
+    {
+        request = acquirePMRequest( this, kIOPMRequestTypeInterestChanged );
+        if (request)
+            submitPMRequest( request );
     }
 
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogInterestedDriver,
-                                            (unsigned long) pm_vars->thePowerStates[pm_vars->myCurrentState].capabilityFlags,2);
-    return  pm_vars->thePowerStates[pm_vars->myCurrentState].capabilityFlags;  // no, return current capability
+    return IOPMNoErr;
 }
 
-
 //*********************************************************************************
-// deRegisterInterestedDriver
+// [private] handleInterestChanged
 //
+// Handle interest added or removed.
 //*********************************************************************************
-IOReturn IOService::deRegisterInterestedDriver ( IOService * theDriver )
+
+void IOService::handleInterestChanged( IOPMRequest * request )
 {
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogRemoveDriver,0,0);
+    IOService *                        driver;
+    IOPMinformee *             informee;
+    IOPMinformeeList * list = fInterestedDrivers;
 
-    priv->interestedDrivers->removeFromList(theDriver);                                  // remove the departing driver
+    PM_LOCK();
 
-    return IOPMNoErr;
-}
+    if (fInsertInterestSet)
+    {
+        while ((driver = (IOService *) fInsertInterestSet->getAnyObject()))
+        {
+            if (list->findItem(driver) == NULL)
+            {
+                informee = list->appendNewInformee(driver);
+            }
+            fInsertInterestSet->removeObject(driver);
+        }
+        fInsertInterestSet->release();
+        fInsertInterestSet = 0;
+    }
+
+    if (fRemoveInterestSet)
+    {
+        while ((driver = (IOService *) fRemoveInterestSet->getAnyObject()))
+        {
+            informee = list->findItem(driver);
+            if (informee)
+            {
+                // Clean-up async interest acknowledgement
+                if (fHeadNotePendingAcks && informee->timer)
+                {
+                    informee->timer = 0;
+                    fHeadNotePendingAcks--;
+                }
+                list->removeFromList(driver);
+            }
+            fRemoveInterestSet->removeObject(driver);
+        }
+        fRemoveInterestSet->release();
+        fRemoveInterestSet = 0;
+    }
 
+    PM_UNLOCK();
+}
 
 //*********************************************************************************
-// acknowledgePowerChange
+// [public] acknowledgePowerChange
 //
 // After we notified one of the interested drivers or a power-domain child
 // of an impending change in power, it has called to say it is now
@@ -792,82 +1460,145 @@ IOReturn IOService::deRegisterInterestedDriver ( IOService * theDriver )
 
 IOReturn IOService::acknowledgePowerChange ( IOService * whichObject )
 {
-   IOPMinformee *      ackingObject;
-   unsigned long       childPower = kIOPMUnknown;
-   IOService *         theChild;
+       IOPMRequest * request;
 
-    ackingObject =  priv->interestedDrivers->findItem(whichObject);                            // one of our interested drivers?
-   if ( ackingObject == NULL ) {
-       if ( ! isChild(whichObject,gIOPowerPlane) ) {
-           pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogAcknowledgeErr1,0,0);
-           kprintf("errant driver: %s\n",whichObject->getName());
-           return IOPMNoErr;                                                   // no, just return
-       }
-       else {
-           pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogChildAcknowledge,priv->head_note_pendingAcks,0);
-       }
-   }
-   else {
-       pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogDriverAcknowledge,priv->head_note_pendingAcks,0);
-   }
+    if (!initialized)
+               return IOPMNotYetInitialized;
+       if (!whichObject)
+               return kIOReturnBadArgument;
 
-   if (! acquire_lock() ) {
-       return IOPMNoErr;
-   }
+       request = acquirePMRequest( this, kIOPMRequestTypeAckPowerChange );
+       if (!request)
+               return kIOReturnNoMemory;
 
-   if (priv->head_note_pendingAcks != 0 ) {                                    // yes, make sure we're expecting acks
-       if ( ackingObject != NULL ) {                                           // it's an interested driver
-           if ( ackingObject->timer != 0 ) {                                   // make sure we're expecting this ack
-               ackingObject->timer = 0;                                                // mark it acked
-               priv->head_note_pendingAcks -= 1;                               // that's one fewer to worry about
-               if ( priv->head_note_pendingAcks == 0 ) {                       // is that the last?
-                   stop_ack_timer();                                           // yes, stop the timer
-                   IOUnlock(priv->our_lock);
-                   all_acked();                                                        // and now we can continue
-                   return IOPMNoErr;
-               }
-           }
-           else {
-               pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogAcknowledgeErr2,0,0); // this driver has already acked
-           kprintf("errant driver: %s\n",whichObject->getName());
-           }
-       }
-       else {                                                                  // it's a child
-            if ( ((IOPowerConnection *)whichObject)->getAwaitingAck() ) {      // make sure we're expecting this ack
-                priv->head_note_pendingAcks -= 1;                              // that's one fewer to worry about
+       whichObject->retain();
+       request->fArg0 = whichObject;
+
+       submitPMRequest( request );
+    return IOPMNoErr;
+}
+
+//*********************************************************************************
+// [private] handleAcknowledgePowerChange
+//*********************************************************************************
+
+bool IOService::handleAcknowledgePowerChange ( IOPMRequest * request )
+{
+    IOPMinformee *             informee;
+    unsigned long              childPower = kIOPMUnknown;
+    IOService *                        theChild;
+       IOService *                     whichObject;
+       bool                            all_acked  = false;
+
+       PM_ASSERT_IN_GATE();
+       whichObject = (IOService *) request->fArg0;
+       assert(whichObject);
+
+    // one of our interested drivers?
+       informee = fInterestedDrivers->findItem( whichObject );
+    if ( informee == NULL )
+    {
+        if ( !isChild(whichObject, gIOPowerPlane) )
+        {
+                       OUR_PMLog(kPMLogAcknowledgeErr1, 0, 0);
+                       goto no_err;
+        } else {
+            OUR_PMLog(kPMLogChildAcknowledge, fHeadNotePendingAcks, 0);
+        }
+    } else {
+        OUR_PMLog(kPMLogDriverAcknowledge, fHeadNotePendingAcks, 0);
+    }
+
+    if ( fHeadNotePendingAcks != 0 )
+    {
+        assert(fPowerStates != NULL);
+
+         // yes, make sure we're expecting acks
+        if ( informee != NULL )
+        {
+            // it's an interested driver
+            // make sure we're expecting this ack
+            if ( informee->timer != 0 )
+            {
+#if LOG_SETPOWER_TIMES
+                if (informee->timer > 0)
+                {
+                    uint64_t nsec = computeTimeDeltaNS(&informee->startTime);
+                    if (nsec > LOG_SETPOWER_TIMES)
+                        PM_LOG("%s::powerState%sChangeTo(%p, %s, %lu -> %lu) async took %d ms\n",
+                            informee->whatObject->getName(),
+                            (fDriverCallReason == kDriverCallInformPreChange) ? "Will" : "Did",
+                            informee->whatObject,
+                            fName, fCurrentPowerState, fHeadNotePowerState, NS_TO_US(nsec));
+                    
+                    uint16_t logType = (fDriverCallReason == kDriverCallInformPreChange) 
+                                            ? kIOPMEventTypePSWillChangeTo
+                                             : kIOPMEventTypePSDidChangeTo;
+
+                    PMEventDetails *details = PMEventDetails::eventDetails(
+                                                logType,
+                                                fName,
+                                                (uintptr_t)this,
+                                                informee->whatObject->getName(),
+                                                0, 0, 0,
+                                                NS_TO_MS(nsec));
+
+                    getPMRootDomain()->recordAndReleasePMEventGated( details );
+                }
+#endif
+                // mark it acked
+                informee->timer = 0;
+                // that's one fewer to worry about
+                fHeadNotePendingAcks--;
+            } else {
+                // this driver has already acked
+                OUR_PMLog(kPMLogAcknowledgeErr2, 0, 0);
+            }
+        } else {
+            // it's a child
+            // make sure we're expecting this ack
+            if ( ((IOPowerConnection *)whichObject)->getAwaitingAck() )
+            {
+                // that's one fewer to worry about
+                fHeadNotePendingAcks--;
                 ((IOPowerConnection *)whichObject)->setAwaitingAck(false);
                 theChild = (IOService *)whichObject->copyChildEntry(gIOPowerPlane);
-                if ( theChild ) {
+                if ( theChild )
+                {
                     childPower = theChild->currentPowerConsumption();
                     theChild->release();
                 }
-                if ( childPower == kIOPMUnknown ) {
-                    pm_vars->thePowerStates[priv->head_note_state].staticPower = kIOPMUnknown;
-                }
-                else {
-                    if ( pm_vars->thePowerStates[priv->head_note_state].staticPower != kIOPMUnknown ) {
-                        pm_vars->thePowerStates[priv->head_note_state].staticPower += childPower;
+                if ( childPower == kIOPMUnknown )
+                {
+                    fHeadNotePowerArrayEntry->staticPower = kIOPMUnknown;
+                } else {
+                    if (fHeadNotePowerArrayEntry->staticPower != kIOPMUnknown)
+                    {
+                        fHeadNotePowerArrayEntry->staticPower += childPower;
                     }
                 }
-                if ( priv->head_note_pendingAcks == 0 ) {                              // is that the last?
-                    stop_ack_timer();                                                  // yes, stop the timer
-                    IOUnlock(priv->our_lock);
-                    all_acked();                                                       // and now we can continue
-                    return IOPMNoErr;
-                }
             }
-       }
+           }
+
+               if ( fHeadNotePendingAcks == 0 ) {
+                       // yes, stop the timer
+                       stop_ack_timer();
+                       // and now we can continue
+                       all_acked = true;
+               }
+    } else {
+        OUR_PMLog(kPMLogAcknowledgeErr3, 0, 0);        // not expecting anybody to ack
     }
-   else {
-       pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogAcknowledgeErr3,0,0); // not expecting anybody to ack
-       kprintf("errant driver: %s\n",whichObject->getName());
-   }
-   IOUnlock(priv->our_lock);
-   return IOPMNoErr;
+
+no_err:
+       if (whichObject)
+               whichObject->release();
+
+    return all_acked;
 }
 
 //*********************************************************************************
-// acknowledgeSetPowerState
+// [public] acknowledgeSetPowerState
 //
 // After we instructed our controlling driver to change power states,
 // it has called to say it has finished doing so.
@@ -876,56 +1607,122 @@ IOReturn IOService::acknowledgePowerChange ( IOService * whichObject )
 
 IOReturn IOService::acknowledgeSetPowerState ( void )
 {
-    if (! acquire_lock() ) {
-        return IOPMNoErr;
-    }
-    if ( priv->driver_timer == -1 ) {
-        priv->driver_timer = 0;                                // driver is acking instead of using return code
-    }
-    else {
-        if ( priv->driver_timer > 0 ) {                        // are we expecting this?
-            stop_ack_timer();                          // yes, stop the timer
-            priv->driver_timer = 0;
-            IOUnlock(priv->our_lock);
-            pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogDriverAcknowledgeSet,0,0);
-            driver_acked();
-            return IOPMNoErr;
-        }
-        else {
-            pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogAcknowledgeErr4,0,0);            // no
-        }
-    }
-    IOUnlock(priv->our_lock);
-    return IOPMNoErr;
+       IOPMRequest * request;
+
+    if (!initialized)
+               return IOPMNotYetInitialized;
+
+       request = acquirePMRequest( this, kIOPMRequestTypeAckSetPowerState );
+       if (!request)
+               return kIOReturnNoMemory;
+
+       submitPMRequest( request );
+       return kIOReturnSuccess;
 }
 
+//*********************************************************************************
+// [private] adjustPowerState
+//*********************************************************************************
+
+void IOService::adjustPowerState ( uint32_t clamp )
+{
+       PM_ASSERT_IN_GATE();
+       computeDesiredState(clamp);
+       if (fControllingDriver && fParentsKnowState && inPlane(gIOPowerPlane))
+       {
+        IOPMPowerChangeFlags changeFlags = kIOPMSelfInitiated;
+
+        // Indicate that children desires were ignored, and do not ask
+        // apps for permission to drop power. This is used by root domain
+        // for demand sleep.
+
+        if (getPMRequestType() == kIOPMRequestTypeRequestPowerStateOverride)
+            changeFlags |= (kIOPMIgnoreChildren | kIOPMSkipAskPowerDown);
+
+               startPowerChange(
+                        /* flags        */     changeFlags,
+                        /* power state  */     fDesiredPowerState,
+                        /* domain flags */     0,
+                        /* connection   */     0,
+                        /* parent flags */     0);
+       }
+}
 
 //*********************************************************************************
-// driver_acked
-//
-// Either the controlling driver has called acknowledgeSetPowerState
-// or the acknowledgement timer has expired while waiting for that.
-// We carry on processing the current change note.
+// [public] synchronizePowerTree
 //*********************************************************************************
 
-void IOService::driver_acked ( void )
+IOReturn IOService::synchronizePowerTree (
+    IOOptionBits    options,
+    IOService *     notifyRoot )
 {
-    switch (priv->machine_state) {
-        case IOPMour_prechange_2:
-            our_prechange_2();
-            break;
-        case IOPMparent_down_5:
-            parent_down_5();
-            break;
-        case IOPMparent_up_4:
-            parent_up_4();
-            break;
+       IOPMRequest *   request_c = 0;
+    IOPMRequest *   request_s;
+
+    if (this != getPMRootDomain())
+        return kIOReturnBadArgument;
+       if (!initialized)
+               return kIOPMNotYetInitialized;
+
+    if (notifyRoot)
+    {
+        IOPMRequest * nr;
+
+        // Cancels don't need to be synchronized.
+        nr = acquirePMRequest(notifyRoot, kIOPMRequestTypeChildNotifyDelayCancel);
+        if (nr) submitPMRequest(nr);        
+        nr = acquirePMRequest(getPMRootDomain(), kIOPMRequestTypeChildNotifyDelayCancel);
+        if (nr) submitPMRequest(nr);
     }
+
+    request_s = acquirePMRequest( this, kIOPMRequestTypeSynchronizePowerTree );
+    if (!request_s)
+        goto error_no_memory;
+
+    if (options & kIOPMSyncCancelPowerDown)
+        request_c = acquirePMRequest( this, kIOPMRequestTypeIdleCancel );
+    if (request_c)
+    {
+        request_c->attachNextRequest( request_s );
+        submitPMRequest(request_c);
+    }
+    
+    request_s->fArg0 = (void *)(uintptr_t) options;
+    submitPMRequest(request_s);
+
+    return kIOReturnSuccess;
+
+error_no_memory:
+       if (request_c) releasePMRequest(request_c);
+       if (request_s) releasePMRequest(request_s);
+    return kIOReturnNoMemory;
 }
 
+//*********************************************************************************
+// [private] handleSynchronizePowerTree
+//*********************************************************************************
+
+void IOService::handleSynchronizePowerTree ( IOPMRequest * request )
+{
+       PM_ASSERT_IN_GATE();
+       if (fControllingDriver && fParentsKnowState && inPlane(gIOPowerPlane) &&
+        (fCurrentPowerState == fNumberOfPowerStates - 1))
+       {
+        IOOptionBits options = (uintptr_t) request->fArg0;
+
+               startPowerChange(
+                        /* flags        */     kIOPMSelfInitiated | kIOPMSynchronize |
+                                (options & kIOPMSyncNoChildNotify),
+                        /* power state  */     fCurrentPowerState,
+                        /* domain flags */     0,
+                        /* connection   */     0,
+                        /* parent flags */     0);
+       }
+}
 
+#ifndef __LP64__
 //*********************************************************************************
-// powerDomainWillChangeTo
+// [deprecated] powerDomainWillChangeTo
 //
 // Called by the power-hierarchy parent notifying of a new power state
 // in the power domain.
@@ -934,65 +1731,117 @@ void IOService::driver_acked ( void )
 // kind of change is occuring in the domain.
 //*********************************************************************************
 
-IOReturn IOService::powerDomainWillChangeTo ( IOPMPowerFlags newPowerStateFlags, IOPowerConnection * whichParent )
+IOReturn IOService::powerDomainWillChangeTo (
+       IOPMPowerFlags          newPowerFlags,
+       IOPowerConnection *     whichParent )
 {
-    OSIterator *                       iter;
-    OSObject *                 next;
-    IOPowerConnection *        connection;
-    unsigned long              newStateNumber;
-    IOPMPowerFlags             combinedPowerFlags;
+       assert(false);
+       return kIOReturnUnsupported;
+}
+#endif /* !__LP64__ */
 
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogWillChange,(unsigned long)newPowerStateFlags,0);
+//*********************************************************************************
+// [private] handlePowerDomainWillChangeTo
+//*********************************************************************************
 
-    if ( ! inPlane(gIOPowerPlane) ) {
-        return IOPMAckImplied;                                         // somebody goofed
-    }
+void IOService::handlePowerDomainWillChangeTo ( IOPMRequest * request )
+{
+       IOPMPowerFlags           parentPowerFlags = (IOPMPowerFlags) request->fArg0;
+       IOPowerConnection *      whichParent = (IOPowerConnection *) request->fArg1;
+    IOPMPowerChangeFlags parentChangeFlags = (IOPMPowerChangeFlags)(uintptr_t) request->fArg2;
+    IOPMPowerChangeFlags myChangeFlags;
+    OSIterator *                iter;
+    OSObject *                  next;
+    IOPowerConnection *         connection;
+    IOPMPowerStateIndex  newPowerState;
+    IOPMPowerFlags              combinedPowerFlags;
+       bool                             savedParentsKnowState;
+       IOReturn                         result = IOPMAckImplied;
+
+       PM_ASSERT_IN_GATE();
+    OUR_PMLog(kPMLogWillChange, parentPowerFlags, 0);
+
+       if (!inPlane(gIOPowerPlane) || !whichParent || !whichParent->getAwaitingAck())
+       {
+               PM_LOG("%s::%s not in power tree\n", getName(), __FUNCTION__);
+        goto exit_no_ack;
+       }
 
-    IOLockLock(pm_vars->parentLock);
-    
-    if ( (pm_vars->PMworkloop == NULL) || (pm_vars->PMcommandGate == NULL) ) {
-        getPMworkloop();                                               // we have a path to the root,
-        if ( pm_vars->PMworkloop != NULL ) {                           // so find out the workloop
-            if ( pm_vars->PMcommandGate == NULL ) {                    // and make our command gate
-                pm_vars->PMcommandGate = IOCommandGate::commandGate((OSObject *)this);
-                if ( pm_vars->PMcommandGate != NULL ) {
-                    pm_vars->PMworkloop->addEventSource(pm_vars->PMcommandGate);
-                }
-            }
-        }
-    }
-    
-    IOLockUnlock(pm_vars->parentLock);
+       savedParentsKnowState = fParentsKnowState;
 
-    combinedPowerFlags = 0;                                            // combine parents' power states
-    
-    iter = getParentIterator(gIOPowerPlane);
+    // Combine parents' output power flags.
 
-    if ( iter ) {
-        while ( (next = iter->getNextObject()) ) {
-            if ( (connection = OSDynamicCast(IOPowerConnection,next)) ) {
-                if ( connection == whichParent ){
-                    combinedPowerFlags |= newPowerStateFlags;
-                }
-                else {
+       combinedPowerFlags = 0;
+
+    iter = getParentIterator(gIOPowerPlane);
+    if ( iter )
+    {
+        while ( (next = iter->getNextObject()) )
+        {
+            if ( (connection = OSDynamicCast(IOPowerConnection, next)) )
+            {
+                if ( connection == whichParent )
+                    combinedPowerFlags |= parentPowerFlags;
+                else
                     combinedPowerFlags |= connection->parentCurrentPowerFlags();
-                }
             }
         }
         iter->release();
     }
-    
-    if  ( pm_vars->theControllingDriver == NULL ) {                                    // we can't take any more action
-        return IOPMAckImplied;
-    }
-    newStateNumber = pm_vars->theControllingDriver->maxCapabilityForDomainState(combinedPowerFlags);
-    return enqueuePowerChange(IOPMParentInitiated | IOPMDomainWillChange,
-                            newStateNumber,combinedPowerFlags,whichParent,newPowerStateFlags); //make the change
-}
 
+    // If our initial change has yet to occur, then defer the power change
+    // until after the power domain has completed its power transition.
+
+    if ( fControllingDriver && !fInitialPowerChange )
+    {
+               newPowerState = fControllingDriver->maxCapabilityForDomainState(
+                                                       combinedPowerFlags);
+
+        // Absorb parent's kIOPMSynchronize flag.
+        myChangeFlags = kIOPMParentInitiated | kIOPMDomainWillChange |
+                        (parentChangeFlags & kIOPMSynchronize);
+
+               result = startPowerChange(
+                 /* flags        */    myChangeFlags,
+                 /* power state  */    newPowerState,
+                                /* domain flags */     combinedPowerFlags,
+                                /* connection   */     whichParent,
+                                /* parent flags */     parentPowerFlags);
+       }
+
+       // If parent is dropping power, immediately update the parent's
+       // capability flags. Any future merging of parent(s) combined
+       // power flags should account for this power drop.
+
+       if (parentChangeFlags & kIOPMDomainPowerDrop)
+       {
+               setParentInfo(parentPowerFlags, whichParent, true);
+       }
+
+       // Parent is expecting an ACK from us. If we did not embark on a state
+       // transition, i.e. startPowerChange() returned IOPMAckImplied. We are
+       // still required to issue an ACK to our parent.
+
+       if (IOPMAckImplied == result)
+       {
+               IOService * parent;
+               parent = (IOService *) whichParent->copyParentEntry(gIOPowerPlane);
+               assert(parent);
+               if ( parent )
+               {
+                       parent->acknowledgePowerChange( whichParent );
+                       parent->release();
+               }
+       }
+
+exit_no_ack:
+    // Drop the retain from notifyChild().
+    if (whichParent) whichParent->release();
+}
 
+#ifndef __LP64__
 //*********************************************************************************
-// powerDomainDidChangeTo
+// [deprecated] powerDomainDidChangeTo
 //
 // Called by the power-hierarchy parent after the power state of the power domain
 // has settled at a new level.
@@ -1001,196 +1850,369 @@ IOReturn IOService::powerDomainWillChangeTo ( IOPMPowerFlags newPowerStateFlags,
 // kind of change is occuring in the domain.
 //*********************************************************************************
 
-IOReturn IOService::powerDomainDidChangeTo ( IOPMPowerFlags newPowerStateFlags, IOPowerConnection * whichParent )
+IOReturn IOService::powerDomainDidChangeTo (
+       IOPMPowerFlags          newPowerFlags,
+       IOPowerConnection *     whichParent )
 {
-    unsigned long newStateNumber;
+       assert(false);
+       return kIOReturnUnsupported;
+}
+#endif /* !__LP64__ */
 
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogDidChange,newPowerStateFlags,0);
+//*********************************************************************************
+// [private] handlePowerDomainDidChangeTo
+//*********************************************************************************
 
-    setParentInfo(newPowerStateFlags,whichParent);
+void IOService::handlePowerDomainDidChangeTo ( IOPMRequest * request )
+{
+       IOPMPowerFlags           parentPowerFlags = (IOPMPowerFlags) request->fArg0;
+       IOPowerConnection *      whichParent = (IOPowerConnection *) request->fArg1;
+    IOPMPowerChangeFlags parentChangeFlags = (IOPMPowerChangeFlags)(uintptr_t) request->fArg2;
+    IOPMPowerChangeFlags myChangeFlags;
+    IOPMPowerStateIndex  newPowerState;
+    IOPMPowerStateIndex  initialDesire;
+       bool                             savedParentsKnowState;
+       IOReturn                         result = IOPMAckImplied;
+
+       PM_ASSERT_IN_GATE();
+    OUR_PMLog(kPMLogDidChange, parentPowerFlags, 0);
+
+       if (!inPlane(gIOPowerPlane) || !whichParent || !whichParent->getAwaitingAck())
+       {
+               PM_LOG("%s::%s not in power tree\n", getName(), __FUNCTION__);
+        goto exit_no_ack;
+       }
 
-    if ( pm_vars->theControllingDriver == NULL ) {
-        return IOPMAckImplied;
-    }
+       savedParentsKnowState = fParentsKnowState;
 
-    newStateNumber = pm_vars->theControllingDriver->maxCapabilityForDomainState(pm_vars->parentsCurrentPowerFlags);
-    return enqueuePowerChange(IOPMParentInitiated | IOPMDomainDidChange,
-                    newStateNumber,pm_vars->parentsCurrentPowerFlags,whichParent,0);   // tell interested parties about it
-}
+    setParentInfo(parentPowerFlags, whichParent, true);
+
+    if ( fControllingDriver )
+       {
+               newPowerState = fControllingDriver->maxCapabilityForDomainState(
+                                                       fParentsCurrentPowerFlags);
+
+        if (fInitialPowerChange)
+        {
+            initialDesire = fControllingDriver->initialPowerStateForDomainState(
+                            fParentsCurrentPowerFlags);
+            computeDesiredState(initialDesire);
+        }
+
+        // Absorb parent's kIOPMSynchronize flag.
+        myChangeFlags = kIOPMParentInitiated | kIOPMDomainDidChange |
+                        (parentChangeFlags & kIOPMSynchronize);
+
+               result = startPowerChange(
+                                /* flags        */     myChangeFlags,
+                 /* power state  */    newPowerState,
+                                /* domain flags */     fParentsCurrentPowerFlags,
+                                /* connection   */     whichParent,
+                                /* parent flags */     0);
+       }
+
+       // Parent is expecting an ACK from us. If we did not embark on a state
+       // transition, i.e. startPowerChange() returned IOPMAckImplied. We are
+       // still required to issue an ACK to our parent.
+
+       if (IOPMAckImplied == result)
+       {
+               IOService * parent;
+               parent = (IOService *) whichParent->copyParentEntry(gIOPowerPlane);
+               assert(parent);
+               if ( parent )
+               {
+                       parent->acknowledgePowerChange( whichParent );
+                       parent->release();
+               }
+       }
+
+       // If the parent registers its power driver late, then this is the
+       // first opportunity to tell our parent about our desire. 
+
+       if (!savedParentsKnowState && fParentsKnowState)
+       {
+               PM_LOG1("%s::powerDomainDidChangeTo parentsKnowState = true\n",
+                       getName());
+               requestDomainPower( fDesiredPowerState );
+       }
 
+exit_no_ack:
+    // Drop the retain from notifyChild().
+    if (whichParent) whichParent->release();
+}
 
 //*********************************************************************************
-// setParentInfo
+// [private] setParentInfo
 //
 // Set our connection data for one specific parent, and then combine all the parent
 // data together.
 //*********************************************************************************
-
-void IOService::setParentInfo ( IOPMPowerFlags newPowerStateFlags, IOPowerConnection * whichParent )
+void IOService::setParentInfo (
+       IOPMPowerFlags          newPowerFlags,
+       IOPowerConnection * whichParent,
+       bool                            knowsState )
 {
-    OSIterator *       iter;
-    OSObject *         next;
-    IOPowerConnection *        connection;
-    
-    whichParent->setParentCurrentPowerFlags(newPowerStateFlags);               // set our connection data
-    whichParent->setParentKnowsState(true);
+    OSIterator *               iter;
+    OSObject *                 next;
+    IOPowerConnection *        conn;
 
-    IOLockLock(pm_vars->parentLock);
+       PM_ASSERT_IN_GATE();
+
+    // set our connection data
+    whichParent->setParentCurrentPowerFlags(newPowerFlags);
+    whichParent->setParentKnowsState(knowsState);
     
-    pm_vars->parentsCurrentPowerFlags = 0;                                     // recompute our parent info
-    pm_vars->parentsKnowState = true;
+    // recompute our parent info
+    fParentsCurrentPowerFlags = 0;
+    fParentsKnowState = true;
 
     iter = getParentIterator(gIOPowerPlane);
-
-    if ( iter ) {
-        while ( (next = iter->getNextObject()) ) {
-            if ( (connection = OSDynamicCast(IOPowerConnection,next)) ) {
-                pm_vars->parentsKnowState &= connection->parentKnowsState();
-                pm_vars->parentsCurrentPowerFlags |= connection->parentCurrentPowerFlags();
+    if ( iter )
+    {
+        while ( (next = iter->getNextObject()) )
+        {
+            if ( (conn = OSDynamicCast(IOPowerConnection, next)) )
+            {
+                fParentsKnowState &= conn->parentKnowsState();
+                fParentsCurrentPowerFlags |= conn->parentCurrentPowerFlags();
             }
         }
         iter->release();
     }
-    IOLockUnlock(pm_vars->parentLock);
 }
 
-
 //*********************************************************************************
-// requestPowerDomainState
+// [private] rebuildChildClampBits
 //
-// The kIOPMPreventIdleSleep and/or kIOPMPreventIdleSleep bits may be be set in the parameter.
-// It is not considered part of the state specification.
+// The ChildClamp bits (kIOPMChildClamp & kIOPMChildClamp2) in our capabilityFlags
+// indicate that one of our children (or grandchildren or great-grandchildren ...)
+// doesn't support idle or system sleep in its current state. Since we don't track
+// the origin of each bit, every time any child changes state we have to clear
+// these bits and rebuild them.
 //*********************************************************************************
-IOReturn IOService::requestPowerDomainState ( IOPMPowerFlags desiredState, IOPowerConnection * whichChild, unsigned long specification )
+
+void IOService::rebuildChildClampBits ( void )
 {
-    unsigned long      i;
-    unsigned long      computedState;
-    unsigned long      theDesiredState = desiredState & ~(kIOPMPreventIdleSleep | kIOPMPreventSystemSleep);
-    OSIterator *       iter;
-    OSObject *         next;
+    unsigned long              i;
+    OSIterator *               iter;
+    OSObject *                 next;
     IOPowerConnection *        connection;
+       unsigned long           powerState;
 
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogRequestDomain,
-                                (unsigned long)desiredState,(unsigned long)specification);
-
-    if ( pm_vars->theControllingDriver == NULL) {
-        return IOPMNotYetInitialized;
+    // A child's desires has changed. We need to rebuild the child-clamp bits in
+       // our power state array. Start by clearing the bits in each power state.
+    
+    for ( i = 0; i < fNumberOfPowerStates; i++ )
+    {
+        fPowerStates[i].capabilityFlags &= ~(kIOPMChildClamp | kIOPMChildClamp2);
     }
 
-    switch (specification) {
-        case IOPMLowestState:
-            i = 0;
-            while ( i < pm_vars->theNumberOfPowerStates ) {
-                if ( ( pm_vars->thePowerStates[i].outputPowerCharacter & theDesiredState) == (theDesiredState & pm_vars->myCharacterFlags) ) {
-                    break;
-                }
-                i++;
-            }
-                if ( i >= pm_vars->theNumberOfPowerStates ) {
-                return IOPMNoSuchState;
-           }
-            break;
+       if (!inPlane(gIOPowerPlane))
+               return;
 
-        case IOPMNextLowerState:
-            i = pm_vars->myCurrentState - 1;
-            while ( i >= 0 ) {
-                if ( ( pm_vars->thePowerStates[i].outputPowerCharacter & theDesiredState) == (theDesiredState & pm_vars->myCharacterFlags) ) {
-                    break;
-                }
-                i--;
-            }
-            if ( i < 0 ) {
-                return IOPMNoSuchState;
-            }
-            break;
+    // Loop through the children. When we encounter the calling child, save the
+       // computed state as this child's desire. And set the ChildClamp bits in any
+    // of our states that some child has clamp on.
 
-        case IOPMHighestState:
-            i = pm_vars->theNumberOfPowerStates;
-            while ( i >= 0 ) {
-                i--;
-                if ( ( pm_vars->thePowerStates[i].outputPowerCharacter & theDesiredState) == (theDesiredState & pm_vars->myCharacterFlags) ) {
-                    break;
+    iter = getChildIterator(gIOPowerPlane);
+    if ( iter )
+    {
+        while ( (next = iter->getNextObject()) )
+        {
+            if ( (connection = OSDynamicCast(IOPowerConnection, next)) )
+            {
+                               if (connection->getReadyFlag() == false)
+                               {
+                                       PM_LOG3("[%s] %s: connection not ready\n",
+                                               getName(), __FUNCTION__);
+                                       continue;
+                               }
+
+                               powerState = connection->getDesiredDomainState();
+                if (powerState < fNumberOfPowerStates)
+                {
+                    if ( connection->getPreventIdleSleepFlag() )
+                        fPowerStates[powerState].capabilityFlags |= kIOPMChildClamp;
+                    if ( connection->getPreventSystemSleepFlag() )
+                        fPowerStates[powerState].capabilityFlags |= kIOPMChildClamp2;
                 }
             }
-            if ( i < 0 ) {
-                return IOPMNoSuchState;
-            }
-            break;
+        }
+        iter->release();
+    }
+}
 
-        case IOPMNextHigherState:
-            i = pm_vars->myCurrentState + 1;
-            while ( i < pm_vars->theNumberOfPowerStates ) {
-                if ( ( pm_vars->thePowerStates[i].outputPowerCharacter & theDesiredState) == (theDesiredState & pm_vars->myCharacterFlags) ) {
-                    break;
-                }
-            i++;
-            }
-                if ( i == pm_vars->theNumberOfPowerStates ) {
-                return IOPMNoSuchState;
-            }
-            break;
+//*********************************************************************************
+// [public] requestPowerDomainState
+//
+// Called on a power parent when a child's power requirement changes.
+//*********************************************************************************
 
-        default:
-            return IOPMBadSpecification;
-    }
+IOReturn IOService::requestPowerDomainState(
+    IOPMPowerFlags      childRequestPowerFlags,
+    IOPowerConnection * childConnection,
+    unsigned long              specification )
+{
+    IOPMPowerStateIndex ps;
+       IOPMPowerFlags          outputPowerFlags;
+    IOService *         child;
+       IOPMRequest *       subRequest;
+    bool                preventIdle, preventSleep; 
+    bool                adjustPower = false;
 
-    computedState = i;
-    
-    IOLockLock(pm_vars->childLock);
+    if (!initialized)
+               return IOPMNotYetInitialized;
 
-// A child's desires has changed.  We need to rebuild the child-clamp bits in our
-// power state array.  Start by clearing the bits in each power state.
-    
-    for ( i = 0; i < pm_vars->theNumberOfPowerStates; i++ ) {
-        pm_vars->thePowerStates[i].capabilityFlags &= ~(kIOPMChildClamp | kIOPMChildClamp2);
+       if (gIOPMWorkLoop->onThread() == false)
+       {
+               PM_LOG("%s::requestPowerDomainState\n", getName());
+               return kIOReturnSuccess;
+       }
+
+    OUR_PMLog(kPMLogRequestDomain, childRequestPowerFlags, specification);
+
+       if (!isChild(childConnection, gIOPowerPlane))
+               return kIOReturnNotAttached;
+
+    if (!fControllingDriver || !fNumberOfPowerStates)
+        return kIOReturnNotReady;
+
+       child = (IOService *) childConnection->getChildEntry(gIOPowerPlane);
+       assert(child);
+
+    preventIdle  = ((childRequestPowerFlags & kIOPMPreventIdleSleep) != 0);
+    preventSleep = ((childRequestPowerFlags & kIOPMPreventSystemSleep) != 0);
+    childRequestPowerFlags &= ~(kIOPMPreventIdleSleep | kIOPMPreventSystemSleep);
+
+    // Merge in the power flags contributed by this power parent
+    // at its current or impending power state. 
+
+    outputPowerFlags = fPowerStates[fCurrentPowerState].outputPowerFlags;
+       if (fMachineState != kIOPM_Finished)
+       {
+               if (IS_POWER_DROP && !IS_ROOT_DOMAIN)
+               {
+                       // Use the lower power state when dropping power. 
+                       // Must be careful since a power drop can be canceled
+                       // from the following states:
+                       // - kIOPM_OurChangeTellClientsPowerDown
+                       // - kIOPM_OurChangeTellPriorityClientsPowerDown
+                       //
+                       // The child must not wait for this parent to raise power
+                       // if the power drop was cancelled. The solution is to cancel
+                       // the power drop if possible, then schedule an adjustment to
+                       // re-evaluate the parent's power state.
+                       //
+                       // Root domain is excluded to avoid idle sleep issues. And permit
+                       // root domain children to pop up when system is going to sleep.
+
+                       if ((fMachineState == kIOPM_OurChangeTellClientsPowerDown) ||
+                               (fMachineState == kIOPM_OurChangeTellPriorityClientsPowerDown))
+                       {
+                               fDoNotPowerDown = true;     // cancel power drop
+                               adjustPower     = true;     // schedule an adjustment
+                               PM_LOG1("%s: power drop cancelled in state %u by %s\n",
+                                       getName(), fMachineState, child->getName());
+                       }
+                       else
+                       {
+                               // Beyond cancellation point, report the impending state.
+                               outputPowerFlags =
+                                       fPowerStates[fHeadNotePowerState].outputPowerFlags;
+                       }
+               }
+               else if (IS_POWER_RISE)
+               {
+                       // When raising power, must report the output power flags from
+                       // child's perspective. A child power request may arrive while
+                       // parent is transitioning upwards. If a request arrives after
+                       // setParentInfo() has already recorded the output power flags
+                       // for the next power state, then using the power supplied by
+                       // fCurrentPowerState is incorrect, and might cause the child
+                       // to wait when it should not.
+                       
+                       outputPowerFlags = childConnection->parentCurrentPowerFlags();
+               }
+    }
+    child->fHeadNoteDomainTargetFlags |= outputPowerFlags;
+
+    // Map child's requested power flags to one of our power state.
+
+    for (ps = 0; ps < fNumberOfPowerStates; ps++)
+    {
+        if ((fPowerStates[ps].outputPowerFlags & childRequestPowerFlags) ==
+            (fOutputPowerCharacterFlags & childRequestPowerFlags))
+            break;
+    }
+    if (ps >= fNumberOfPowerStates)
+    {
+        ps = 0;  // should never happen
     }
 
-// Now loop through the children.  When we encounter the calling child, save
-// the computed state as this child's desire.  And while we're at it, set the ChildClamp bits
-// in any of our states that some child has requested with clamp on.
+    // Conditions that warrants a power adjustment on this parent.
+    // Adjust power will also propagate any changes to the child's
+    // prevent idle/sleep flags towards the root domain.
 
-    iter = getChildIterator(gIOPowerPlane);
+    if (!childConnection->childHasRequestedPower() ||
+        (ps != childConnection->getDesiredDomainState()) ||
+        (childConnection->getPreventIdleSleepFlag() != preventIdle) ||
+        (childConnection->getPreventSystemSleepFlag() != preventSleep))
+        adjustPower = true;
 
-    if ( iter ) {
-        while ( (next = iter->getNextObject()) ) {
-            if ( (connection = OSDynamicCast(IOPowerConnection,next)) ) {
-                if ( connection == whichChild ) {
-                    connection->setDesiredDomainState(computedState);
-                    connection->setPreventIdleSleepFlag(desiredState & kIOPMPreventIdleSleep);
-                    connection->setPreventSystemSleepFlag(desiredState & kIOPMPreventSystemSleep);
-                    connection->setChildHasRequestedPower();
-                }
-                if ( connection->getPreventIdleSleepFlag() ) {
-                    pm_vars->thePowerStates[connection->getDesiredDomainState()].capabilityFlags |= kIOPMChildClamp;
-                }
-                if ( connection->getPreventSystemSleepFlag() ) {
-                    pm_vars->thePowerStates[connection->getDesiredDomainState()].capabilityFlags |= kIOPMChildClamp2;
-                }
-            }
-        }
-        iter->release();
-    }
-        
-    IOLockUnlock(pm_vars->childLock);
-    
-    computeDesiredState();                             // this may be different now
+#if ENABLE_DEBUG_LOGS
+    if (adjustPower)
+    {
+        PM_LOG("requestPowerDomainState[%s]: %s, init %d, %u->%u\n",
+            getName(), child->getName(),
+            !childConnection->childHasRequestedPower(),
+            (uint32_t) childConnection->getDesiredDomainState(),
+            (uint32_t) ps);
+    }
+#endif
+
+       // Record the child's desires on the connection.
+#if SUPPORT_IDLE_CANCEL
+       bool attemptCancel = (preventIdle && !childConnection->getPreventIdleSleepFlag());
+#endif
+       childConnection->setChildHasRequestedPower();
+       childConnection->setDesiredDomainState( ps );
+       childConnection->setPreventIdleSleepFlag( preventIdle );
+       childConnection->setPreventSystemSleepFlag( preventSleep );
+
+       // Schedule a request to re-evaluate all children desires and
+       // adjust power state. Submit a request if one wasn't pending,
+       // or if the current request is part of a call tree.
+
+    if (adjustPower && !fDeviceOverrideEnabled &&
+        (!fAdjustPowerScheduled || gIOPMRequest->getRootRequest()))
+    {
+               subRequest = acquirePMRequest(
+            this, kIOPMRequestTypeAdjustPowerState, gIOPMRequest );
+               if (subRequest)
+               {
+                       submitPMRequest( subRequest );
+                       fAdjustPowerScheduled = true;
+               }
+    }
+
+#if SUPPORT_IDLE_CANCEL
+       if (attemptCancel)
+       {
+               subRequest = acquirePMRequest( this, kIOPMRequestTypeIdleCancel );
+               if (subRequest)
+               {
+                       submitPMRequest( subRequest );
+               }
+       }
+#endif
 
-   if ( inPlane(gIOPowerPlane) &&
-        (pm_vars->parentsKnowState) ) {
-       changeState();                                  // change state if all children can now tolerate lower power
-   }
-   
-   if ( priv->clampOn ) {                              // are we clamped on, waiting for this child?
-       priv->clampOn = false;                          // yes, remove the clamp
-       changePowerStateToPriv(0);
-   }
-   
-   return IOPMNoErr;
+    return kIOReturnSuccess;
 }
 
-
 //*********************************************************************************
-// temporaryPowerClampOn
+// [public] temporaryPowerClampOn
 //
 // A power domain wants to clamp its power on till it has children which
 // will thendetermine the power domain state.
@@ -1200,14 +2222,11 @@ IOReturn IOService::requestPowerDomainState ( IOPMPowerFlags desiredState, IOPow
 
 IOReturn IOService::temporaryPowerClampOn ( void )
 {
-    priv->clampOn = true;
-    makeUsable();
-    return IOPMNoErr;
+    return requestPowerState( gIOPMPowerClientChildProxy, kIOPMPowerStateMax );
 }
 
-
 //*********************************************************************************
-// makeUsable
+// [public] makeUsable
 //
 // Some client of our device is asking that we become usable.  Although
 // this has not come from a subclassed device object, treat it exactly
@@ -1220,2095 +2239,2756 @@ IOReturn IOService::temporaryPowerClampOn ( void )
 
 IOReturn IOService::makeUsable ( void )
 {
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogMakeUsable,0,0);
-
-    if ( pm_vars->theControllingDriver == NULL ) {
-        priv->need_to_become_usable = true;
-        return IOPMNoErr;
-    }
-    priv->deviceDesire = pm_vars->theNumberOfPowerStates - 1;
-    computeDesiredState();
-    if ( inPlane(gIOPowerPlane) && (pm_vars->parentsKnowState) ) {
-        return changeState();
-    }
-    return IOPMNoErr;
+    OUR_PMLog(kPMLogMakeUsable, 0, 0);
+    return requestPowerState( gIOPMPowerClientDevice, kIOPMPowerStateMax );
 }
 
-
 //*********************************************************************************
-// currentCapability
-//
+// [public] currentCapability
 //*********************************************************************************
 
 IOPMPowerFlags IOService::currentCapability ( void )
 {
-    if ( pm_vars->theControllingDriver == NULL ) {
-        return 0;
-    }
-    else {
-        return   pm_vars->thePowerStates[pm_vars->myCurrentState].capabilityFlags;
-    }
-}
+       if (!initialized)
+               return IOPMNotPowerManaged;
 
+    return fCurrentCapabilityFlags;
+}
 
 //*********************************************************************************
-// changePowerStateTo
+// [public] changePowerStateTo
 //
-// For some reason, our power-controlling driver has decided it needs to change
-// power state.  We enqueue the power change so that appropriate parties
-// will be notified, and then we will instruct the driver to make the change.
+// Called by our power-controlling driver to change power state. The new desired
+// power state is computed and compared against the current power state. If those
+// power states differ, then a power state change is initiated.
 //*********************************************************************************
 
 IOReturn IOService::changePowerStateTo ( unsigned long ordinal )
 {
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogChangeStateTo,ordinal,0);
-
-    if ( ordinal >= pm_vars->theNumberOfPowerStates ) {
-        return IOPMParameterError;
-    }
-    priv->driverDesire = ordinal;
-    computeDesiredState();
-    if ( inPlane(gIOPowerPlane) && (pm_vars->parentsKnowState) ) {
-        return changeState();
-    }
-
-    return IOPMNoErr;
+    OUR_PMLog(kPMLogChangeStateTo, ordinal, 0);
+    return requestPowerState( gIOPMPowerClientDriver, ordinal );
 }
 
 //*********************************************************************************
-// changePowerStateToPriv
+// [protected] changePowerStateToPriv
 //
-// For some reason, a subclassed device object has decided it needs to change
-// power state.  We enqueue the power change so that appropriate parties
-// will be notified, and then we will instruct the driver to make the change.
+// Called by our driver subclass to change power state. The new desired power
+// state is computed and compared against the current power state. If those
+// power states differ, then a power state change is initiated.
 //*********************************************************************************
 
 IOReturn IOService::changePowerStateToPriv ( unsigned long ordinal )
 {
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogChangeStateToPriv,ordinal,0);
+    OUR_PMLog(kPMLogChangeStateToPriv, ordinal, 0);
+    return requestPowerState( gIOPMPowerClientDevice, ordinal );
+}
 
-    if ( pm_vars->theControllingDriver == NULL) {
-        return IOPMNotYetInitialized;
-    }
-    if ( ordinal >= pm_vars->theNumberOfPowerStates ) {
-        return IOPMParameterError;
-    }
-    priv->deviceDesire = ordinal;
-    computeDesiredState();
-    if ( inPlane(gIOPowerPlane) && (pm_vars->parentsKnowState) ) {
-        return changeState();
-    }
+//*********************************************************************************
+// [protected] changePowerStateWithOverrideTo
+//
+// Called by our driver subclass to change power state. The new desired power
+// state is computed and compared against the current power state. If those
+// power states differ, then a power state change is initiated.
+// Override enforced - Children and Driver desires are ignored.
+//*********************************************************************************
+
+IOReturn IOService::changePowerStateWithOverrideTo ( unsigned long ordinal )
+{
+       IOPMRequest * request;
+
+       if (!initialized)
+               return kIOPMNotYetInitialized;
+
+    OUR_PMLog(kPMLogChangeStateToPriv, ordinal, 0);
+
+       request = acquirePMRequest( this, kIOPMRequestTypeRequestPowerStateOverride );
+       if (!request)
+               return kIOReturnNoMemory;
+
+    gIOPMPowerClientDevice->retain();
+    request->fArg0 = (void *) ordinal;
+    request->fArg1 = (void *) gIOPMPowerClientDevice;
+    request->fArg2 = 0;
+#if NOT_READY
+    if (action)
+        request->installCompletionAction( action, target, param );
+#endif
+
+       // Prevent needless downwards power transitions by clamping power
+       // until the scheduled request is executed.
+
+       if (gIOPMWorkLoop->inGate() && (ordinal < fNumberOfPowerStates))
+       {
+               fTempClampPowerState = max(fTempClampPowerState, ordinal);
+               fTempClampCount++;
+               fOverrideMaxPowerState = ordinal;
+               request->fArg2 = (void *) (uintptr_t) true;
+       }
 
+       submitPMRequest( request );
     return IOPMNoErr;
 }
 
+//*********************************************************************************
+// [private] requestPowerState
+//*********************************************************************************
+
+IOReturn IOService::requestPowerState (
+    const OSSymbol *      client,
+    uint32_t              state )
+{
+       IOPMRequest * request;
+
+    if (!client)
+        return kIOReturnBadArgument;
+       if (!initialized)
+               return kIOPMNotYetInitialized;
+
+       request = acquirePMRequest( this, kIOPMRequestTypeRequestPowerState );
+       if (!request)
+               return kIOReturnNoMemory;
+
+    client->retain();
+    request->fArg0 = (void *) state;
+    request->fArg1 = (void *) client;
+    request->fArg2 = 0;
+#if NOT_READY
+    if (action)
+        request->installCompletionAction( action, target, param );
+#endif
+
+       // Prevent needless downwards power transitions by clamping power
+       // until the scheduled request is executed.
+
+       if (gIOPMWorkLoop->inGate() && (state < fNumberOfPowerStates))
+       {
+               fTempClampPowerState = max(fTempClampPowerState, state);
+               fTempClampCount++;
+               request->fArg2 = (void *) (uintptr_t) true;
+       }
+
+       submitPMRequest( request );
+    return IOPMNoErr;
+}
 
 //*********************************************************************************
-// computeDesiredState
-//
+// [private] handleRequestPowerState
 //*********************************************************************************
 
-void IOService::computeDesiredState ( void )
+void IOService::handleRequestPowerState ( IOPMRequest * request )
 {
-    OSIterator *       iter;
-    OSObject *         next;
-    IOPowerConnection *        connection;
-    unsigned long      newDesiredState = 0;
+    const OSSymbol * client = (const OSSymbol *)    request->fArg1;
+    uint32_t         state  = (uint32_t)(uintptr_t) request->fArg0;
+
+       PM_ASSERT_IN_GATE();
+       if (request->fArg2)
+       {
+               assert(fTempClampCount != 0);
+               if (fTempClampCount)  fTempClampCount--;
+               if (!fTempClampCount) fTempClampPowerState = 0;
+       }
 
-    // Compute the maximum  of our children's desires, our controlling driver's desire, and the subclass device's desire.
+       if (fNumberOfPowerStates && (state >= fNumberOfPowerStates))
+               state = fNumberOfPowerStates - 1;
 
-    if ( !  priv->device_overrides ) {
-        iter = getChildIterator(gIOPowerPlane);
+    // The power suppression due to changePowerStateWithOverrideTo() expires
+    // upon the next "device" power request - changePowerStateToPriv().
 
-        if ( iter ) {
-            while ( (next = iter->getNextObject()) ) {
-                if ( (connection = OSDynamicCast(IOPowerConnection,next)) ) {
-                    if ( connection->getDesiredDomainState() > newDesiredState ) {
-                        newDesiredState = connection->getDesiredDomainState();
-                    }
-                }
-            }
-            iter->release();
-        }
-        
-        if (  priv->driverDesire > newDesiredState ) {
-            newDesiredState =  priv->driverDesire;
-        }
-    }
+    if ((getPMRequestType() != kIOPMRequestTypeRequestPowerStateOverride) &&
+        (client == gIOPMPowerClientDevice))
+        fOverrideMaxPowerState = kIOPMPowerStateMax;
 
-    if ( priv->deviceDesire > newDesiredState ) {
-        newDesiredState = priv->deviceDesire;
-    }
+    if ((state == 0) &&
+               (client != gIOPMPowerClientDevice) &&
+               (client != gIOPMPowerClientDriver) &&
+               (client != gIOPMPowerClientChildProxy))
+               removePowerClient(client);
+       else
+               updatePowerClient(client, state);
 
-    priv->ourDesiredPowerState = newDesiredState;
+       adjustPowerState();
+    client->release();
 }
 
-
 //*********************************************************************************
-// changeState
-//
-// A subclass object, our controlling driver, or a power domain child
-// has asked for a different power state.  Here we compute what new
-// state we should enter and enqueue the change (or start it).
+// [private] Helper functions to update/remove power clients.
 //*********************************************************************************
 
-IOReturn IOService::changeState ( void )
+void IOService::updatePowerClient( const OSSymbol * client, uint32_t powerState )
 {
-    if ( (pm_vars->theControllingDriver == NULL) ||    // if not fully initialized
-         ! (inPlane(gIOPowerPlane)) ||
-       ! (pm_vars->parentsKnowState) ) {
-        return IOPMNoErr;                              // we can do no more
+    if (!fPowerClients)
+        fPowerClients = OSDictionary::withCapacity(4);
+    if (fPowerClients && client)
+    {
+        OSNumber * num = (OSNumber *) fPowerClients->getObject(client);
+        if (num)
+            num->setValue(powerState);
+        else
+        {
+            num = OSNumber::withNumber(powerState, 32);
+            if (num)
+            {
+                fPowerClients->setObject(client, num);
+                num->release();
+            }
+        }
     }
-    
-    return enqueuePowerChange(IOPMWeInitiated,priv->ourDesiredPowerState,0,0,0);
 }
 
+void IOService::removePowerClient( const OSSymbol * client )
+{
+    if (fPowerClients && client)
+        fPowerClients->removeObject(client);
+}
+
+uint32_t IOService::getPowerStateForClient( const OSSymbol * client )
+{
+    uint32_t powerState = 0;
+
+    if (fPowerClients && client)
+    {
+        OSNumber * num = (OSNumber *) fPowerClients->getObject(client);
+        if (num) powerState = num->unsigned32BitValue();
+    }
+    return powerState;
+}
 
 //*********************************************************************************
-// currentPowerConsumption
-//
+// [protected] powerOverrideOnPriv
 //*********************************************************************************
 
-unsigned long IOService::currentPowerConsumption ( void )
+IOReturn IOService::powerOverrideOnPriv ( void )
 {
-    if ( pm_vars->theControllingDriver == NULL ) {
-        return kIOPMUnknown;
-    }
-    if ( pm_vars->thePowerStates[pm_vars->myCurrentState].capabilityFlags & kIOPMStaticPowerValid ) {
-        return  pm_vars->thePowerStates[pm_vars->myCurrentState].staticPower;
-    }
-    return kIOPMUnknown;
+       IOPMRequest * request;
+
+    if (!initialized)
+               return IOPMNotYetInitialized;
+
+       if (gIOPMWorkLoop->inGate())
+       {
+               fDeviceOverrideEnabled = true;
+               return IOPMNoErr;
+       }
+
+       request = acquirePMRequest( this, kIOPMRequestTypePowerOverrideOnPriv );
+       if (!request)
+               return kIOReturnNoMemory;
+
+       submitPMRequest( request );
+    return IOPMNoErr;
 }
 
 //*********************************************************************************
-// activityTickle
-//
-// The activity tickle with parameter kIOPMSubclassPolicyis not handled
-// here and should have been intercepted by the subclass.
-// The tickle with parameter kIOPMSuperclassPolicy1 causes the activity
-// flag to be set, and the device state checked.  If the device has been
-// powered down, it is powered up again.
+// [protected] powerOverrideOffPriv
 //*********************************************************************************
 
-bool IOService::activityTickle ( unsigned long type, unsigned long stateNumber=0 )
+IOReturn IOService::powerOverrideOffPriv ( void )
 {
-    AbsoluteTime uptime;
+       IOPMRequest * request;
 
-    if ( type == kIOPMSuperclassPolicy1 ) {
-        if ( (priv->activityLock == NULL) ||
-             (pm_vars->theControllingDriver == NULL) ||
-             (pm_vars->commandQueue == NULL) ) {
-            return true;
-        }
-        IOTakeLock(priv->activityLock);
-        priv->device_active = true;
+    if (!initialized)
+               return IOPMNotYetInitialized;
 
-        clock_get_uptime(&uptime);
-        priv->device_active_timestamp = uptime;
+       if (gIOPMWorkLoop->inGate())
+       {
+               fDeviceOverrideEnabled = false;
+               return IOPMNoErr;
+       }
 
-        if ( pm_vars->myCurrentState >= stateNumber) {
-            IOUnlock(priv->activityLock);
-            return true;
-        }
-        IOUnlock(priv->activityLock);                          // send a message on the command queue
-        pm_vars->commandQueue->enqueueCommand(true, (void *)kIOPMUnidleDevice, (void *)stateNumber);
-        return false;
-    }
-    return true;
+       request = acquirePMRequest( this, kIOPMRequestTypePowerOverrideOffPriv );
+       if (!request)
+               return kIOReturnNoMemory;
+
+       submitPMRequest( request );
+    return IOPMNoErr;
 }
 
 //*********************************************************************************
-// getPMworkloop
-//
-// A child is calling to get a pointer to the Power Management workloop.
-// We got it or get it from one of our parents.
+// [private] handlePowerOverrideChanged
 //*********************************************************************************
 
-IOWorkLoop * IOService::getPMworkloop ( void )
+void IOService::handlePowerOverrideChanged ( IOPMRequest * request )
 {
-IOService * nub;
-IOService * parent;
+       PM_ASSERT_IN_GATE();
+       if (request->getType() == kIOPMRequestTypePowerOverrideOnPriv)
+       {
+               OUR_PMLog(kPMLogOverrideOn, 0, 0);
+               fDeviceOverrideEnabled = true;
+    }
+       else
+       {
+               OUR_PMLog(kPMLogOverrideOff, 0, 0);
+               fDeviceOverrideEnabled = false;
+       }
 
-    if ( ! inPlane(gIOPowerPlane) ) {
-        return NULL;
-    }
-    if ( pm_vars->PMworkloop == NULL ) {                               // we have no workloop yet
-        nub = (IOService *)copyParentEntry(gIOPowerPlane);
-        if ( nub ) {
-            parent = (IOService *)nub->copyParentEntry(gIOPowerPlane);
-            nub->release();
-            if ( parent ) {                                            // ask one of our parents for the workloop
-                pm_vars->PMworkloop = parent->getPMworkloop();
-                parent->release();
-            }
-        }
-    }
-    return  pm_vars->PMworkloop;
+       adjustPowerState();
 }
 
-
 //*********************************************************************************
-// setIdleTimerPeriod
-//
-// A subclass policy-maker is going to use our standard idleness
-// detection service.  Make a command queue and an idle timer and
-// connect them to the power management workloop.  Finally,
-// start the timer.
+// [private] computeDesiredState
 //*********************************************************************************
 
-IOReturn  IOService::setIdleTimerPeriod ( unsigned long period )
+void IOService::computeDesiredState ( unsigned long localClamp )
 {
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMsetIdleTimerPeriod,period, 0);
+    OSIterator *               iter;
+    OSObject *                 next;
+    IOPowerConnection *        connection;
+       uint32_t            desiredState  = 0;
+    uint32_t            newPowerState = 0;
+    bool                hasChildren   = false;
 
-    priv->idle_timer_period = period;
+       // Desired power state is always 0 without a controlling driver.
 
-    if ( period > 0 ) {
-        if ( getPMworkloop() == NULL ) {
-            return kIOReturnError;
-        }
+       if (!fNumberOfPowerStates)
+       {
+        fDesiredPowerState = 0;
+               //PM_LOG("%s::%s no controlling driver\n", getName(), __FUNCTION__);
+               return;
+       }
 
-        if (pm_vars->commandQueue == NULL ) {          // make the command queue
-            pm_vars->commandQueue = IOCommandQueue::commandQueue(this, PMreceiveCmd);
-            if (!  pm_vars->commandQueue ||
-                (  pm_vars->PMworkloop->addEventSource( pm_vars->commandQueue) != kIOReturnSuccess) ) {
-                return kIOReturnError;
-            }
-        }
-                                                        // make the timer event
-        if (  priv->timerEventSrc == NULL ) {
-            priv->timerEventSrc = IOTimerEventSource::timerEventSource(this,
-                                                    PM_idle_timer_expired);
-            if ( !  priv->timerEventSrc ||
-                 ( pm_vars->PMworkloop->addEventSource(  priv->timerEventSrc) != kIOReturnSuccess) ) {
-                return kIOReturnError;
+    // Examine the children's desired power state.
+
+    iter = getChildIterator(gIOPowerPlane);
+    if (iter)
+    {
+        while ((next = iter->getNextObject()))
+        {
+            if ((connection = OSDynamicCast(IOPowerConnection, next)))
+            {
+                if (connection->getReadyFlag() == false)
+                {
+                    PM_LOG3("[%s] %s: connection not ready\n",
+                        getName(), __FUNCTION__);
+                    continue;
+                }
+                if (connection->childHasRequestedPower())
+                    hasChildren = true;
+                if (connection->getDesiredDomainState() > desiredState)
+                    desiredState = connection->getDesiredDomainState();
             }
         }
+        iter->release();
+    }
+    if (hasChildren)
+        updatePowerClient(gIOPMPowerClientChildren, desiredState);
+    else
+        removePowerClient(gIOPMPowerClientChildren);
 
-        if ( priv->activityLock == NULL ) {
-            priv->activityLock = IOLockAlloc();
-        }
+    // Iterate through all power clients to determine the min power state.
 
-        start_PM_idle_timer();
+    iter = OSCollectionIterator::withCollection(fPowerClients);
+    if (iter)
+    {
+        const OSSymbol * client;
+        while ((client = (const OSSymbol *) iter->getNextObject()))
+        {
+                       // Ignore child and driver when override is in effect.
+            if ((fDeviceOverrideEnabled ||
+                (getPMRequestType() == kIOPMRequestTypeRequestPowerStateOverride)) &&
+                ((client == gIOPMPowerClientChildren) ||
+                 (client == gIOPMPowerClientDriver)))
+                continue;
+
+                       // Ignore child proxy when children are present.
+            if (hasChildren && (client == gIOPMPowerClientChildProxy))
+                continue;
+
+            desiredState = getPowerStateForClient(client);
+            assert(desiredState < fNumberOfPowerStates);                       
+                       PM_LOG1("  %u %s\n",
+                               desiredState, client->getCStringNoCopy());
+
+            newPowerState = max(newPowerState, desiredState);
+
+            if (client == gIOPMPowerClientDevice)
+                fDeviceDesire = desiredState;
+        }
+        iter->release();
     }
-    return IOPMNoErr;
-}
 
+    // Factor in the temporary power desires.
 
-//*********************************************************************************
-// start_PM_idle_timer
-//
-// The parameter is a pointer to us.  Use it to call our timeout method.
-//*********************************************************************************
-void IOService::start_PM_idle_timer ( void )
-{
-    AbsoluteTime uptime;
-    AbsoluteTime delta;
-    UInt64       delta_ns;
-    UInt64       delta_secs;
-    UInt64       delay_secs;
+    newPowerState = max(newPowerState, localClamp);
+    newPowerState = max(newPowerState, fTempClampPowerState);
 
-    IOLockLock(priv->activityLock);
+    // Limit check against max power override.
 
-    clock_get_uptime(&uptime);
+    newPowerState = min(newPowerState, fOverrideMaxPowerState);
 
-   /* Calculate time difference using funky macro from clock.h.
-    */
-    delta = uptime;
-    SUB_ABSOLUTETIME(&delta, &(priv->device_active_timestamp));
+    // Limit check against number of power states.
 
-   /* Figure it in seconds.
-    */
-    absolutetime_to_nanoseconds(delta, &delta_ns);
-    delta_secs = delta_ns / NSEC_PER_SEC;
+    if (newPowerState >= fNumberOfPowerStates)
+        newPowerState = fNumberOfPowerStates - 1;
 
-   /* Be paranoid about delta somehow exceeding timer period.
-    */
-    if (delta_secs < priv->idle_timer_period ) {
-        delay_secs = priv->idle_timer_period - delta_secs;
-    } else {
-        delay_secs = priv->idle_timer_period;
-    }
+    fDesiredPowerState = newPowerState;
 
-    priv->timerEventSrc->setTimeout(delay_secs, NSEC_PER_SEC);
+    PM_LOG1("  temp %u, clamp %u, current %u, new %u\n",
+        (uint32_t) localClamp, (uint32_t) fTempClampPowerState,
+               (uint32_t) fCurrentPowerState, newPowerState);
 
-    IOLockUnlock(priv->activityLock);
-    return;
-}
+       // Restart idle timer if stopped and device desire has increased.
+
+       if (fDeviceDesire && fIdleTimerStopped)
+       {
+               fIdleTimerStopped = false;
+        fActivityTickleCount = 0;
+               clock_get_uptime(&fIdleTimerStartTime);
+               start_PM_idle_timer();
+       }
 
+       // Invalidate cached tickle power state when desires change, and not
+       // due to a tickle request.  This invalidation must occur before the
+       // power state change to minimize races.  We want to err on the side
+       // of servicing more activity tickles rather than dropping one when
+       // the device is in a low power state.
+
+       if ((getPMRequestType() != kIOPMRequestTypeActivityTickle) &&
+               (fActivityTicklePowerState != -1))
+       {
+               IOLockLock(fActivityLock);
+               fActivityTicklePowerState = -1;
+               IOLockUnlock(fActivityLock);
+       }
+}
 
 //*********************************************************************************
-// PM_idle_timer_expired
+// [public] currentPowerConsumption
 //
-// The parameter is a pointer to us.  Use it to call our timeout method.
 //*********************************************************************************
 
-void PM_idle_timer_expired(OSObject * ourSelves, IOTimerEventSource *)
+unsigned long IOService::currentPowerConsumption ( void )
 {
-    ((IOService *)ourSelves)->PM_idle_timer_expiration();
-}
+    if (!initialized)
+        return kIOPMUnknown;
 
+    return fCurrentPowerConsumption;
+}
 
 //*********************************************************************************
-// PM_idle_timer_expiration
-//
-// The idle timer has expired.  If there has been activity since the last
-// expiration, just restart the timer and return.  If there has not been
-// activity, switch to the next lower power state and restart the timer.
+// [deprecated] getPMworkloop
 //*********************************************************************************
 
-void IOService::PM_idle_timer_expiration ( void )
+IOWorkLoop * IOService::getPMworkloop ( void )
 {
-    if ( ! initialized ) {
-        return;                                        // we're unloading
-    }
-
-    if (  priv->idle_timer_period > 0 ) {
-        IOTakeLock(priv->activityLock);
-        if ( priv->device_active ) {
-            priv->device_active = false;
-            IOUnlock(priv->activityLock);
-            start_PM_idle_timer();
-            return;
-        }
-        if ( pm_vars->myCurrentState > 0 ) {
-            IOUnlock(priv->activityLock);
-            changePowerStateToPriv(pm_vars->myCurrentState - 1);
-            start_PM_idle_timer();
-            return;
-        }
-        IOUnlock(priv->activityLock);
-        start_PM_idle_timer();
-    }
+       return gIOPMWorkLoop;
 }
 
+#if NOT_YET
 
+//*********************************************************************************
+// Power Parent/Children Applier
+//*********************************************************************************
 
-// **********************************************************************************
-// PMreceiveCmd
-//
-//
-//
-// **********************************************************************************
-void PMreceiveCmd ( OSObject * theDriver,  void * command, void * param1, void * param2, void *param3 )
+static void
+applyToPowerChildren( 
+    IOService *               service,
+    IOServiceApplierFunction  applier,
+    void *                    context,
+    IOOptionBits              options )
 {
-   ((IOService *)theDriver)->command_received(command,param1,param2,param3);
-}
+       PM_ASSERT_IN_GATE();
 
+    IORegistryEntry *       entry;
+    IORegistryIterator *    iter;
+    IOPowerConnection *     connection;
+    IOService *             child;
 
-// **********************************************************************************
-// command_received
-//
-// We have received a command from ourselves on the command queue.
-// This is to prevent races with timer-expiration code.
-// **********************************************************************************
-void IOService::command_received ( void * command, void *stateNumber , void * , void *)
-{
-    if ( ! initialized ) {
-        return;                                        // we're unloading
+    iter = IORegistryIterator::iterateOver(service, gIOPowerPlane, options);
+    if (iter)
+    {
+        while ((entry = iter->getNextObject()))
+        {
+            // Get child of IOPowerConnection objects
+            if ((connection = OSDynamicCast(IOPowerConnection, entry)))
+            {
+                child = (IOService *) connection->copyChildEntry(gIOPowerPlane);
+                if (child)
+                {
+                    (*applier)(child, context);
+                    child->release();
+                }
+            }
+        }
+        iter->release();
     }
+}
 
-    if ( command == (void *)kIOPMUnidleDevice ) {
-        if ( (pm_vars->myCurrentState < (unsigned long)stateNumber) &&
-            (priv->imminentState < (unsigned long)stateNumber) ) {
-            changePowerStateToPriv((unsigned long)stateNumber);
+static void
+applyToPowerParent( 
+    IOService *               service,
+    IOServiceApplierFunction  applier,
+    void *                    context,
+    IOOptionBits              options )
+{
+       PM_ASSERT_IN_GATE();
+
+    IORegistryEntry *       entry;
+    IORegistryIterator *    iter;
+    IOPowerConnection *     connection;
+    IOService *             parent;
+
+    iter = IORegistryIterator::iterateOver(service, gIOPowerPlane,
+            options | kIORegistryIterateParents);
+    if (iter)
+    {
+        while ((entry = iter->getNextObject()))
+        {
+            // Get child of IOPowerConnection objects
+            if ((connection = OSDynamicCast(IOPowerConnection, entry)))
+            {
+                parent = (IOService *) connection->copyParentEntry(gIOPowerPlane);
+                if (parent)
+                {
+                    (*applier)(parent, context);
+                    parent->release();
+                }
+            }
         }
+        iter->release();
     }
 }
 
+#endif /* NOT_YET */
+
+// MARK: -
+// MARK: Activity Tickle & Idle Timer
 
 //*********************************************************************************
-// setAggressiveness
+// [public] activityTickle
 //
-// Pass on the input parameters to all power domain children. All those which are
-// power domains will pass it on to their children, etc.
+// The tickle with parameter kIOPMSuperclassPolicy1 causes the activity
+// flag to be set, and the device state checked.  If the device has been
+// powered down, it is powered up again.
+// The tickle with parameter kIOPMSubclassPolicy is ignored here and
+// should be intercepted by a subclass.
 //*********************************************************************************
 
-IOReturn IOService::setAggressiveness ( unsigned long type, unsigned long newLevel )
+bool IOService::activityTickle ( unsigned long type, unsigned long stateNumber )
 {
-    OSIterator *       iter;
-    OSObject *         next;
-    IOPowerConnection *        connection;
-    IOService *         child;
+       IOPMRequest *   request;
+       bool                    noPowerChange = true;
 
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogSetAggressiveness,type, newLevel);
+    if ( initialized && stateNumber && (type == kIOPMSuperclassPolicy1) )
+       {
+        IOLockLock(fActivityLock);
 
-    if ( type <= kMaxType ) {
-        pm_vars->current_aggressiveness_values[type] = newLevel;
-        pm_vars->current_aggressiveness_valid[type] = true;
-    }
+               // Record device activity for the idle timer handler.
 
-    iter = getChildIterator(gIOPowerPlane);
+        fDeviceWasActive = true;
+        fActivityTickleCount++;
+        clock_get_uptime(&fDeviceActiveTimestamp);
 
-    if ( iter ) {
-        while ( (next = iter->getNextObject()) ) {
-            if ( (connection = OSDynamicCast(IOPowerConnection,next)) ) {
-                child = ((IOService *)(connection->copyChildEntry(gIOPowerPlane)));
-                if ( child ) {
-                    child->setAggressiveness(type, newLevel);
-                    child->release();
-                }
-            }
-        }
-        iter->release();
-    }
+        PM_ACTION_0(actionActivityTickle);
 
-    return IOPMNoErr;
+               // Record the last tickle power state.
+               // This helps to filter out redundant tickles as
+               // this function may be called from the data path.
+
+               if (fActivityTicklePowerState < (long)stateNumber)
+               {
+                       fActivityTicklePowerState = stateNumber;
+                       noPowerChange = false;
+
+                       request = acquirePMRequest( this, kIOPMRequestTypeActivityTickle );
+                       if (request)
+                       {
+                               request->fArg0 = (void *) stateNumber;  // power state
+                               request->fArg1 = (void *) (uintptr_t) true;     // power rise
+                               submitPMRequest(request);
+                       }
+               }
+
+               IOLockUnlock(fActivityLock);
+       }
+
+       // Returns false if the activityTickle might cause a transition to a
+       // higher powered state, true otherwise.
+
+    return noPowerChange;
 }
 
 //*********************************************************************************
-// getAggressiveness
-//
-// Called by the user client.
+// [private] handleActivityTickle
 //*********************************************************************************
 
-IOReturn IOService::getAggressiveness ( unsigned long type, unsigned long * currentLevel )
+void IOService::handleActivityTickle ( IOPMRequest * request )
 {
-  if ( type <= kMaxType ) {
-        *currentLevel = pm_vars->current_aggressiveness_values[type];
-  }
-    return kIOReturnSuccess;
+       uint32_t ticklePowerState = (uint32_t)(uintptr_t) request->fArg0;
+       bool     adjustPower = false;
+
+       PM_ASSERT_IN_GATE();
+       if (request->fArg1)
+       {
+               // Power rise from activity tickle.
+               if ((ticklePowerState > fDeviceDesire) &&
+                       (ticklePowerState < fNumberOfPowerStates))
+               {
+                       fIdleTimerMinPowerState = ticklePowerState;
+                       adjustPower = true;
+               }
+       }
+       else if (fDeviceDesire > fIdleTimerMinPowerState)
+       {
+               // Power drop due to idle timer expiration.
+               // Do not allow idle timer to reduce power below tickle power.          
+               ticklePowerState = fDeviceDesire - 1;
+               adjustPower = true;
+       }
+
+       if (adjustPower)
+       {
+               updatePowerClient(gIOPMPowerClientDevice, ticklePowerState);
+               adjustPowerState();
+       }
 }
 
-//*********************************************************************************
-// systemWake
+//******************************************************************************
+// [public] setIdleTimerPeriod
 //
-// Pass this to all power domain children. All those which are
-// power domains will pass it on to their children, etc.
-//*********************************************************************************
+// A subclass policy-maker is using our standard idleness detection service.
+// Start the idle timer. Period is in seconds.
+//******************************************************************************
 
-IOReturn IOService::systemWake ( void )
+IOReturn IOService::setIdleTimerPeriod ( unsigned long period )
 {
-    OSIterator *       iter;
-    OSObject *         next;
-    IOPowerConnection *        connection;
-    IOService *                theChild;
+    if (!initialized)
+               return IOPMNotYetInitialized;
 
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogSystemWake,0, 0);
-
-    iter = getChildIterator(gIOPowerPlane);
+    OUR_PMLog(kPMLogSetIdleTimerPeriod, period, fIdleTimerPeriod);
 
-    if ( iter ) {
-        while ( (next = iter->getNextObject()) ) {
-            if ( (connection = OSDynamicCast(IOPowerConnection,next)) ) {
-                theChild = (IOService *)connection->copyChildEntry(gIOPowerPlane);
-                if ( theChild ) {
-                       theChild->systemWake();
-                        theChild->release();
-                }
-            }
-        }
-        iter->release();
-    }
+    IOPMRequest * request =
+        acquirePMRequest( this, kIOPMRequestTypeSetIdleTimerPeriod );
+    if (!request)
+        return kIOReturnNoMemory;
 
-    if ( pm_vars->theControllingDriver != NULL ) {
-        if ( pm_vars->theControllingDriver->didYouWakeSystem() ) {
-            makeUsable();
-        }
-    }
+    request->fArg0 = (void *) period;
+    submitPMRequest( request );
 
-    return IOPMNoErr;
+    return kIOReturnSuccess;
 }
 
-
-//*********************************************************************************
-// temperatureCriticalForZone
+//******************************************************************************
+// [public] nextIdleTimeout
 //
-//*********************************************************************************
+// Returns how many "seconds from now" the device should idle into its
+// next lowest power state.
+//******************************************************************************
 
-IOReturn IOService::temperatureCriticalForZone ( IOService * whichZone )
+SInt32 IOService::nextIdleTimeout(
+    AbsoluteTime currentTime,
+    AbsoluteTime lastActivity, 
+    unsigned int powerState)
 {
-    IOService * theParent;
-    IOService * theNub;
+    AbsoluteTime        delta;
+    UInt64              delta_ns;
+    SInt32              delta_secs;
+    SInt32              delay_secs;
+
+    // Calculate time difference using funky macro from clock.h.
+    delta = currentTime;
+    SUB_ABSOLUTETIME(&delta, &lastActivity);
     
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogCriticalTemp,0,0);
+    // Figure it in seconds.
+    absolutetime_to_nanoseconds(delta, &delta_ns);
+    delta_secs = (SInt32)(delta_ns / NSEC_PER_SEC);
 
-    if ( inPlane(gIOPowerPlane) && ! (priv->we_are_root) ) {
-        theNub = (IOService *)copyParentEntry(gIOPowerPlane);
-        if ( theNub ) {
-            theParent = (IOService *)theNub->copyParentEntry(gIOPowerPlane);
-            theNub->release();
-            if ( theParent ) {
-                theParent->temperatureCriticalForZone(whichZone);
-                theParent->release();
-            }
-        }
-    }
-    return IOPMNoErr;
+    // Be paranoid about delta somehow exceeding timer period.
+    if (delta_secs < (int) fIdleTimerPeriod)
+        delay_secs = (int) fIdleTimerPeriod - delta_secs;
+    else
+        delay_secs = (int) fIdleTimerPeriod;
+    
+    return (SInt32)delay_secs;
 }
 
-
 //*********************************************************************************
-// powerOverrideOnPriv
-//
+// [public] start_PM_idle_timer
 //*********************************************************************************
 
-
-IOReturn IOService::powerOverrideOnPriv ( void )
+void IOService::start_PM_idle_timer ( void )
 {
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogOverrideOn,0,0);
+    static const int    maxTimeout = 100000;
+    static const int    minTimeout = 1;
+    AbsoluteTime        uptime, deadline;
+    SInt32              idle_in = 0;
+       boolean_t           pending;
 
-    priv->device_overrides = true;     // turn on the override
-    computeDesiredState();
-    return changeState();              // change state if that changed something
-}
+       if (!initialized || !fIdleTimerPeriod)
+               return;
+
+    IOLockLock(fActivityLock);
+
+    clock_get_uptime(&uptime);
+
+    // Subclasses may modify idle sleep algorithm
+    idle_in = nextIdleTimeout(uptime, fDeviceActiveTimestamp, fCurrentPowerState);
+
+    // Check for out-of range responses
+    if (idle_in > maxTimeout)
+    {
+        // use standard implementation
+        idle_in = IOService::nextIdleTimeout(uptime,
+                        fDeviceActiveTimestamp,
+                        fCurrentPowerState);
+    } else if (idle_in < minTimeout) {
+        idle_in = fIdleTimerPeriod;
+    }
+
+    IOLockUnlock(fActivityLock);
 
+    retain();
+    clock_interval_to_absolutetime_interval(idle_in, kSecondScale, &deadline);
+    ADD_ABSOLUTETIME(&deadline, &uptime);
+    pending = thread_call_enter_delayed(fIdleTimer, deadline);
+    if (pending) release();
+}
 
 //*********************************************************************************
-// powerOverrideOffPriv
-//
+// idle_timer_expired
 //*********************************************************************************
-IOReturn IOService::powerOverrideOffPriv ( void )
+
+static void
+idle_timer_expired (
+    thread_call_param_t arg0, thread_call_param_t arg1 )
 {
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogOverrideOff,0,0);
+       IOService * me = (IOService *) arg0;
 
-    priv->device_overrides = false;    // turn off the override
-    computeDesiredState();
-    if( priv->clampOn)
-        return makeUsable();
-    else
-        return changeState();          // change state if that changed something
-}
+       if (gIOPMWorkLoop)
+               gIOPMWorkLoop->runAction(
+            OSMemberFunctionCast(IOWorkLoop::Action, me,
+                &IOService::idleTimerExpired),
+            me);
 
+       me->release();
+}
 
 //*********************************************************************************
-// enqueuePowerChange
-//
-// Allocate a new state change notification, initialize it with fields from the
-// caller, and add it to the tail of the list of pending power changes.
+// [private] idleTimerExpired
 //
-// If it is early enough in the list, and almost all the time it is the only one in
-// the list, start the power change.
-//
-// In rare instances, this change will preempt the previous change in the list.
-// If the previous change is un-actioned in any way (because we are still
-// processing an even earlier power change), and if both the previous change
-// in the list and this change are initiated by us (not the parent), then we
-// needn't perform the previous change, so we collapse the list a little.
+// The idle timer has expired. If there has been activity since the last
+// expiration, just restart the timer and return.  If there has not been
+// activity, switch to the next lower power state and restart the timer.
 //*********************************************************************************
 
-IOReturn IOService::enqueuePowerChange ( unsigned long flags,  unsigned long whatStateOrdinal, unsigned long domainState, IOPowerConnection * whichParent, unsigned long singleParentState )
+void IOService::idleTimerExpired( void )
 {
-    long       newNote;
-    long       previousNote;
+       IOPMRequest *   request;
+       bool                    restartTimer = true;
 
-// Create and initialize the new change note
+    if ( !initialized || !fIdleTimerPeriod || fLockedFlags.PMStop )
+        return;
 
-    IOLockLock(priv->queue_lock);
-    newNote = priv->changeList->createChangeNote();
-    if ( newNote == -1 ) {
-        IOLockUnlock(priv->queue_lock);
-        pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogEnqueueErr,0,0);
-        return IOPMAckImplied;                 // uh-oh, our list is full
-    }
+       IOLockLock(fActivityLock);
 
-    priv->changeList->changeNote[newNote].newStateNumber = whatStateOrdinal;
-    priv->changeList->changeNote[newNote].outputPowerCharacter =  pm_vars->thePowerStates[whatStateOrdinal].outputPowerCharacter;
-    priv->changeList->changeNote[newNote].inputPowerRequirement =  pm_vars->thePowerStates[whatStateOrdinal].inputPowerRequirement;
-    priv->changeList->changeNote[newNote].capabilityFlags =  pm_vars->thePowerStates[whatStateOrdinal].capabilityFlags;
-    priv->changeList->changeNote[newNote].flags = flags;
-    if (flags & IOPMParentInitiated ) {
-        priv->changeList->changeNote[newNote].domainState =  domainState;
-        priv->changeList->changeNote[newNote].parent =  whichParent;
-        whichParent->retain();
-        priv->changeList->changeNote[newNote].singleParentState =  singleParentState;
-    }
+       // Check for device activity (tickles) over last timer period.
 
-    previousNote = priv->changeList->previousChangeNote(newNote);
+       if (fDeviceWasActive)
+       {
+               // Device was active - do not drop power, restart timer.
+               fDeviceWasActive = false;
+       }
+       else
+       {
+               // No device activity - drop power state by one level.
+               // Decrement the cached tickle power state when possible.
+               // This value may be (-1) before activityTickle() is called,
+               // but the power drop request must be issued regardless.
 
-    if ( previousNote == -1 ) {
+               if (fActivityTicklePowerState > 0)
+               {
+                       fActivityTicklePowerState--;
+               }
 
-        // Queue is empty, we can start this change.
+               request = acquirePMRequest( this, kIOPMRequestTypeActivityTickle );
+               if (request)
+               {
+                       request->fArg0 = (void *) 0;            // power state (irrelevant)
+                       request->fArg1 = (void *) (uintptr_t) false;    // power drop
+                       submitPMRequest( request );
 
-        if (flags & IOPMWeInitiated ) {
-            IOLockUnlock(priv->queue_lock);
-            start_our_change(newNote);
-            return 0;
-        }
-        else {
-            IOLockUnlock(priv->queue_lock);
-            return start_parent_change(newNote);
-        }
+                       // Do not restart timer until after the tickle request has been
+                       // processed.
+
+                       restartTimer = false;
+               }
     }
 
-    // The queue is not empty.  Try to collapse this new change and the previous one in queue into one change.
-    // This is possible only if both changes are initiated by us, and neither has been started yet.
-    // Do this more than once if possible.
+       IOLockUnlock(fActivityLock);
 
-    // (A change is started iff it is at the head of the queue)
-
-    while ( (previousNote != priv->head_note) &&  (previousNote != -1) &&
-            (priv->changeList->changeNote[newNote].flags &  priv->changeList->changeNote[previousNote].flags &  IOPMWeInitiated)  ) {
-        priv->changeList->changeNote[previousNote].outputPowerCharacter = priv->changeList->changeNote[newNote].outputPowerCharacter;
-        priv->changeList->changeNote[previousNote].inputPowerRequirement = priv->changeList->changeNote[newNote].inputPowerRequirement;
-        priv->changeList->changeNote[previousNote].capabilityFlags =priv-> changeList->changeNote[newNote].capabilityFlags;
-        pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogCollapseQueue,priv->changeList->changeNote[newNote].newStateNumber,
-                                                                    priv->changeList->changeNote[previousNote].newStateNumber);
-        priv->changeList->changeNote[previousNote].newStateNumber = priv->changeList->changeNote[newNote].newStateNumber;
-        priv->changeList->releaseTailChangeNote();
-        newNote = previousNote;
-        previousNote = priv->changeList->previousChangeNote(newNote);
-    }
-    IOLockUnlock(priv->queue_lock);
-    return IOPMWillAckLater;                           // in any case, we can't start yet
+       if (restartTimer)
+               start_PM_idle_timer();
 }
 
+#ifndef __LP64__
 //*********************************************************************************
-// notifyAll
-//
-// Notify all interested parties either that a change is impending or that the
-// previously-notified change is done and power has settled.
-// The parameter identifies whether this is the
-// pre-change notification or the post-change notification.
-//
+// [deprecated] PM_idle_timer_expiration
 //*********************************************************************************
 
-IOReturn IOService::notifyAll ( bool is_prechange )
+void IOService::PM_idle_timer_expiration ( void )
 {
-    IOPMinformee *             nextObject;
-    OSIterator *                       iter;
-    OSObject *                 next;
-    IOPowerConnection *        connection;
-
-    // To prevent acknowledgePowerChange from finishing the change note and removing it from the queue if
-    // some driver calls it, we inflate the number of pending acks so it cannot become zero.  We'll fix it later.
-
-    priv->head_note_pendingAcks =1;
-
-    // OK, we will go through the lists of interested drivers and power domain children
-    // and notify each one of this change.
-    nextObject =  priv->interestedDrivers->firstInList();              // notify interested drivers
-    while (  nextObject != NULL ) {
-        priv->head_note_pendingAcks +=1;
-        if (! inform(nextObject, is_prechange) ) {
-        }
-        nextObject  =  priv->interestedDrivers->nextInList(nextObject);
-    }
-
-    if (! acquire_lock() ) {
-        return IOPMNoErr;
-    }
-    if ( priv->head_note_pendingAcks > 1 ) {                                   // did they all ack?
-        pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogStartAckTimer,0,0);  // no
-        start_ack_timer();
-    }
-    IOUnlock(priv->our_lock);                                                  // either way
-
-    iter = getChildIterator(gIOPowerPlane);                            // notify children
-    pm_vars->thePowerStates[priv->head_note_state].staticPower = 0;     // summing their power consumption
+}
 
-    if ( iter ) {
-        while ( (next = iter->getNextObject()) ) {
-            if ( (connection = OSDynamicCast(IOPowerConnection,next)) ) {
-                priv->head_note_pendingAcks +=1;
-                notifyChild(connection, is_prechange);
-            }
-        }
-        iter->release();
-    }
+//*********************************************************************************
+// [deprecated] command_received
+//*********************************************************************************
 
-    if (! acquire_lock() ) {
-        return IOPMNoErr;
-    }
-    priv->head_note_pendingAcks -= 1;                  // now make this real
-    if (priv->head_note_pendingAcks == 0 ) {           // is it all acked?
-        IOUnlock(priv->our_lock);                      // yes
-        return IOPMAckImplied;                         // return ack to parent
-    }
-    IOUnlock(priv->our_lock);                          // no
-    return IOPMWillAckLater;
+void IOService::command_received ( void *statePtr , void *, void * , void * )
+{
 }
-
+#endif /* !__LP64__ */
 
 //*********************************************************************************
-// notifyChild
+// [public] setAggressiveness
 //
-// Notify a power domain child of an upcoming power change.
-//
-// If the object acknowledges the current change, we return TRUE.
+// Pass on the input parameters to all power domain children. All those which are
+// power domains will pass it on to their children, etc.
 //*********************************************************************************
 
-bool IOService::notifyChild ( IOPowerConnection * theNub, bool is_prechange )
+IOReturn IOService::setAggressiveness ( unsigned long type, unsigned long newLevel )
 {
-    IOReturn           k = IOPMAckImplied;
-    unsigned long      childPower;
-    IOService *                theChild = (IOService *)(theNub->copyChildEntry(gIOPowerPlane));
-
-   theNub->setAwaitingAck(true);                                       // in case they don't ack
-   
-   if ( ! theChild ) {
-        return true;
-   }
-   
-   if ( is_prechange ) {
-       k = theChild->powerDomainWillChangeTo(priv->head_note_outputFlags,theNub);
-   }
-   else {
-       k = theChild->powerDomainDidChangeTo(priv->head_note_outputFlags,theNub);
-   }
-
-   if ( k == IOPMAckImplied ) {                                                // did the return code ack?
-       priv->head_note_pendingAcks -=1;                                // yes
-        theNub->setAwaitingAck(false);
-        childPower = theChild->currentPowerConsumption();
-        if ( childPower == kIOPMUnknown ) {
-            pm_vars->thePowerStates[priv->head_note_state].staticPower = kIOPMUnknown;
-        }
-        else {
-            if ( pm_vars->thePowerStates[priv->head_note_state].staticPower != kIOPMUnknown ) {
-                pm_vars->thePowerStates[priv->head_note_state].staticPower += childPower;
-            }
-        }
-        theChild->release();
-       return true;
-   }
-   theChild->release();
-   return false;
+    return kIOReturnSuccess;
 }
 
-
 //*********************************************************************************
-// inform
-//
-// Notify an interested driver of an upcoming power change.
+// [public] getAggressiveness
 //
-// If the object acknowledges the current change, we return TRUE.
+// Called by the user client.
 //*********************************************************************************
 
-bool IOService::inform ( IOPMinformee * nextObject, bool is_prechange )
+IOReturn IOService::getAggressiveness ( unsigned long type, unsigned long * currentLevel )
 {
-    IOReturn k = IOPMAckImplied;
-
-   nextObject->timer = -1;                                     // initialize this
+    IOPMrootDomain *    rootDomain = getPMRootDomain();
 
-   if ( is_prechange ) {
-       pm_vars->thePlatform->PMLog (pm_vars->ourName,PMlogInformDriverPreChange,
-                                    (unsigned long)priv->head_note_capabilityFlags,(unsigned long)priv->head_note_state);
-       k = nextObject->whatObject->powerStateWillChangeTo( priv->head_note_capabilityFlags,priv->head_note_state,this);
-   }
-   else {
-       pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogInformDriverPostChange,
-                                   (unsigned long)priv->head_note_capabilityFlags,(unsigned long)priv->head_note_state);
-       k = nextObject->whatObject->powerStateDidChangeTo(priv->head_note_capabilityFlags,priv->head_note_state,this);
-   }
-   if ( nextObject->timer == 0 ) {                             // did it ack behind our back?
-       return true;                                            // yes
-   }
-   if ( k ==IOPMAckImplied ) {                                 // no, did the return code ack?
-       nextObject->timer = 0;                                  // yes
-       priv->head_note_pendingAcks -= 1;
-       return true;
-   }
-   if ( k < 0 ) {
-       nextObject->timer = 0;                                  // somebody goofed
-       priv-> head_note_pendingAcks -= 1;
-       return true;
-  }
-   nextObject->timer = (k * ns_per_us / ACK_TIMER_PERIOD) + 1; // no, it's a timer
-   return false;
+    if (!rootDomain)
+        return kIOReturnNotReady;
+    
+    return rootDomain->getAggressiveness( type, currentLevel );
 }
 
-
 //*********************************************************************************
-// our_prechange_03
+// [public] getPowerState
 //
-// All registered applications and kernel clients have positively acknowledged our
-// intention of lowering power.  Here we notify them all that we will definitely
-// lower the power.  If we don't have to wait for any of them to acknowledge, we
-// carry on by notifying interested drivers.  Otherwise, we do wait.
 //*********************************************************************************
 
-void IOService::our_prechange_03 ( void )
+UInt32 IOService::getPowerState ( void )
 {
-    priv->machine_state = IOPMour_prechange_04;                // next state
-    if ( tellChangeDown1(priv->head_note_state) ) {    // are we waiting for responses?
-        our_prechange_04();                            // no, notify priority clients
-    }
-}
+    if (!initialized)
+        return 0;
 
+    return fCurrentPowerState;
+}
 
+#ifndef __LP64__
 //*********************************************************************************
-// our_prechange_04
+// [deprecated] systemWake
 //
-// All registered applications and kernel clients have positively acknowledged our
-// intention of lowering power.  Here we notify "priority" clients that we are
-// lowering power.  If we don't have to wait for any of them to acknowledge, we
-// carry on by notifying interested drivers.  Otherwise, we do wait.
+// Pass this to all power domain children. All those which are
+// power domains will pass it on to their children, etc.
 //*********************************************************************************
 
-void IOService::our_prechange_04 ( void )
+IOReturn IOService::systemWake ( void )
 {
-    priv->machine_state = IOPMour_prechange_05;                // next state
-    if ( tellChangeDown2(priv->head_note_state) ) {    // are we waiting for responses?
-        return our_prechange_05();                      // no, notify interested drivers
+    OSIterator *               iter;
+    OSObject *                 next;
+    IOPowerConnection *        connection;
+    IOService *                        theChild;
+
+    iter = getChildIterator(gIOPowerPlane);
+    if ( iter )
+    {
+        while ( (next = iter->getNextObject()) )
+        {
+            if ( (connection = OSDynamicCast(IOPowerConnection, next)) )
+            {
+                               if (connection->getReadyFlag() == false)
+                               {
+                                       PM_LOG3("[%s] %s: connection not ready\n",
+                                               getName(), __FUNCTION__);
+                                       continue;
+                               }
+
+                theChild = (IOService *)connection->copyChildEntry(gIOPowerPlane);
+                if ( theChild )
+                {
+                       theChild->systemWake();
+                    theChild->release();
+                }
+            }
+        }
+        iter->release();
+    }
+
+    if ( fControllingDriver != NULL )
+    {
+        if ( fControllingDriver->didYouWakeSystem() )
+        {
+            makeUsable();
+        }
     }
-}
 
+    return IOPMNoErr;
+}
 
 //*********************************************************************************
-// our_prechange_05
-//
-// All registered applications and kernel clients have acknowledged our notification
-// that we are lowering power.  Here we notify interested drivers.  If we don't have
-// to wait for any of them to acknowledge, we instruct our power driver to make the change.
-// Otherwise, we do wait.
+// [deprecated] temperatureCriticalForZone
 //*********************************************************************************
 
-void IOService::our_prechange_05 ( void )
+IOReturn IOService::temperatureCriticalForZone ( IOService * whichZone )
 {
-    priv->machine_state = IOPMour_prechange_1;         // no, in case they don't all ack
-    if ( notifyAll(true) == IOPMAckImplied ) {
-        our_prechange_1();
+    IOService *        theParent;
+    IOService *        theNub;
+    
+    OUR_PMLog(kPMLogCriticalTemp, 0, 0);
+
+    if ( inPlane(gIOPowerPlane) && !IS_PM_ROOT )
+    {
+        theNub = (IOService *)copyParentEntry(gIOPowerPlane);
+        if ( theNub )
+        {
+            theParent = (IOService *)theNub->copyParentEntry(gIOPowerPlane);
+            theNub->release();
+            if ( theParent )
+            {
+                theParent->temperatureCriticalForZone(whichZone);
+                theParent->release();
+            }
+        }
     }
+    return IOPMNoErr;
 }
+#endif /* !__LP64__ */
 
+// MARK: -
+// MARK: Power Change (Common)
 
 //*********************************************************************************
-// our_prechange_1
+// [private] startPowerChange
 //
-// All interested drivers have acknowledged our pre-change notification of a power
-// change we initiated.  Here we instruct our controlling driver to make
-// the change to the hardware.  If it does so, we continue processing
-// (waiting for settle and notifying interested parties post-change.)
-// If it doesn't, we have to wait for it to acknowledge and then continue.
+// All power state changes starts here.
 //*********************************************************************************
 
-void IOService::our_prechange_1 ( void )
+IOReturn IOService::startPowerChange(
+    IOPMPowerChangeFlags    changeFlags,
+    IOPMPowerStateIndex     powerState,
+    IOPMPowerFlags          domainFlags,
+    IOPowerConnection *     parentConnection,
+    IOPMPowerFlags          parentFlags )
 {
-    if ( instruct_driver(priv->head_note_state) == IOPMAckImplied ) {
-        our_prechange_2();                                     // it's done, carry on
-    }
-    else {
-        priv->machine_state = IOPMour_prechange_2;             // it's not, wait for it
-        pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogStartAckTimer,0,0);
-        start_ack_timer();
-    }
-}
+       PM_ASSERT_IN_GATE();
+       assert( fMachineState == kIOPM_Finished );
+    assert( powerState < fNumberOfPowerStates );
 
+    if (powerState >= fNumberOfPowerStates)
+        return IOPMAckImplied;
+
+    fIsPreChange = true;
+    PM_ACTION_2(actionPowerChangeOverride, &powerState, &changeFlags);
+
+       // Forks to either Driver or Parent initiated power change paths.
+
+    fHeadNoteChangeFlags      = changeFlags;
+    fHeadNotePowerState       = powerState;
+       fHeadNotePowerArrayEntry  = &fPowerStates[ powerState ];
+       fHeadNoteParentConnection = NULL;
+
+       if (changeFlags & kIOPMSelfInitiated)
+       {
+        if (changeFlags & kIOPMSynchronize)
+            OurSyncStart();
+        else
+            OurChangeStart();
+               return 0;
+       }
+       else
+       {
+               assert(changeFlags & kIOPMParentInitiated);
+        fHeadNoteDomainFlags = domainFlags;
+               fHeadNoteParentFlags = parentFlags;
+        fHeadNoteParentConnection = parentConnection;
+               return ParentChangeStart();
+       }
+}
 
 //*********************************************************************************
-// our_prechange_2
-//
-// Our controlling driver has changed power state on the hardware
-// during a power change we initiated.  Here we see if we need to wait
-// for power to settle before continuing.  If not, we continue processing
-// (notifying interested parties post-change).  If so, we wait and
-// continue later.
+// [private] notifyInterestedDrivers
 //*********************************************************************************
 
-void IOService::our_prechange_2 ( void )
+bool IOService::notifyInterestedDrivers ( void )
 {
-    priv->settle_time = compute_settle_time();
-    if ( priv->settle_time == 0 ) {
-       our_prechange_3();
+    IOPMinformee *             informee;
+    IOPMinformeeList * list = fInterestedDrivers;
+    DriverCallParam *  param;
+    IOItemCount                        count;
+
+    PM_ASSERT_IN_GATE();
+    assert( fDriverCallParamCount == 0 );
+    assert( fHeadNotePendingAcks == 0 );
+
+    fHeadNotePendingAcks = 0;
+
+    count = list->numberOfItems();
+    if (!count)
+        goto done;     // no interested drivers
+
+    // Allocate an array of interested drivers and their return values
+    // for the callout thread. Everything else is still "owned" by the
+    // PM work loop, which can run to process acknowledgePowerChange()
+    // responses.
+
+    param = (DriverCallParam *) fDriverCallParamPtr;
+    if (count > fDriverCallParamSlots)
+    {
+        if (fDriverCallParamSlots)
+        {
+            assert(fDriverCallParamPtr);
+            IODelete(fDriverCallParamPtr, DriverCallParam, fDriverCallParamSlots);
+            fDriverCallParamPtr = 0;
+            fDriverCallParamSlots = 0;
+        }
+
+        param = IONew(DriverCallParam, count);
+        if (!param)
+            goto done; // no memory
+
+        fDriverCallParamPtr   = (void *) param;
+        fDriverCallParamSlots = count;
     }
-    else {
-        priv->machine_state = IOPMour_prechange_3;
-        startSettleTimer(priv->settle_time);
+
+    informee = list->firstInList();
+    assert(informee);
+    for (IOItemCount i = 0; i < count; i++)
+    {
+        informee->timer = -1;
+        param[i].Target = informee;
+        informee->retain();
+        informee = list->nextInList( informee );
     }
-}
 
+    fDriverCallParamCount = count;
+    fHeadNotePendingAcks  = count;
 
-//*********************************************************************************
-// our_prechange_3
-//
-// Power has settled on a power change we initiated.  Here we notify
-// all our interested parties post-change.  If they all acknowledge, we're
-// done with this change note, and we can start on the next one.
-// Otherwise we have to wait for acknowledgements and finish up later.
-//*********************************************************************************
+    // Block state machine and wait for callout completion.
+    assert(!fDriverCallBusy);
+    fDriverCallBusy = true;
+    thread_call_enter( fDriverCallEntry );
+    return true;
 
-void IOService::our_prechange_3 ( void )
-{
-    priv->machine_state = IOPMour_prechange_4;         // in case they don't all ack
-    if ( notifyAll(false) == IOPMAckImplied ) {
-        our_prechange_4();
-    }
+done:
+    // Return false if there are no interested drivers or could not schedule
+    // callout thread due to error.
+    return false;
 }
 
-
 //*********************************************************************************
-// our_prechange_4
-//
-// Power has settled on a power change we initiated, and
-// all our interested parties have acknowledged.  We're
-// done with this change note, and we can start on the next one.
+// [private] notifyInterestedDriversDone
 //*********************************************************************************
 
-void IOService::our_prechange_4 ( void )
+void IOService::notifyInterestedDriversDone ( void )
 {
-    all_done();
-}
+    IOPMinformee *             informee;
+    IOItemCount                        count;
+    DriverCallParam *   param;
+    IOReturn            result;
+
+       PM_ASSERT_IN_GATE();
+       assert( fDriverCallBusy == false );
+       assert( fMachineState == kIOPM_DriverThreadCallDone );
+
+       param = (DriverCallParam *) fDriverCallParamPtr;
+       count = fDriverCallParamCount;
+
+       if (param && count)
+       {
+               for (IOItemCount i = 0; i < count; i++, param++)
+               {
+                       informee = (IOPMinformee *) param->Target;
+                       result   = param->Result;
+
+                       if ((result == IOPMAckImplied) || (result < 0))
+                       {
+                               // Interested driver return IOPMAckImplied.
+                // If informee timer is zero, it must have de-registered
+                // interest during the thread callout. That also drops
+                // the pending ack count.
+
+                               if (fHeadNotePendingAcks && informee->timer)
+                    fHeadNotePendingAcks--;
+
+                informee->timer = 0;
+                       }
+                       else if (informee->timer)
+                       {
+                assert(informee->timer == -1);
+
+                // Driver has not acked, and has returned a positive result.
+                // Enforce a minimum permissible timeout value.
+                // Make the min value large enough so timeout is less likely
+                // to occur if a driver misinterpreted that the return value
+                // should be in microsecond units.  And make it large enough
+                // to be noticeable if a driver neglects to ack.
+
+                if (result < kMinAckTimeoutTicks)
+                    result = kMinAckTimeoutTicks;
+
+                informee->timer = (result / (ACK_TIMER_PERIOD / ns_per_us)) + 1;
+                       }
+                       // else, child has already acked or driver has removed interest,
+            // and head_note_pendingAcks decremented.
+                       // informee may have been removed from the interested drivers list,
+            // thus the informee must be retained across the callout.
+
+                       informee->release();
+               }
+
+               fDriverCallParamCount = 0;
+
+               if ( fHeadNotePendingAcks )
+               {
+                       OUR_PMLog(kPMLogStartAckTimer, 0, 0);
+                       start_ack_timer();
+               }
+       }
 
+    MS_POP();  // pushed by notifyAll()
 
-//*********************************************************************************
-// parent_down_0
-//
-// All applications and kernel clients have been notified of a power lowering
-// initiated by the parent and we didn't have to wait for any responses.  Here
-// we notify any priority clients.  If they all ack, we continue with the power change.
-// If at least one doesn't, we have to wait for it to acknowledge and then continue.
-//*********************************************************************************
+    // If interest acks are outstanding, wait for fHeadNotePendingAcks to become
+    // zero before notifying children. This enforces the children after interest
+    // ordering even for async interest clients.
 
-IOReturn IOService::parent_down_0 ( void )
-{
-    priv->machine_state = IOPMparent_down_05;           // in case they don't all ack
-    if ( tellChangeDown2(priv->head_note_state) ) {    // are we waiting for responses?
-        return parent_down_02();                       // no, notify interested drivers
+    if (!fHeadNotePendingAcks)
+    {
+        notifyChildren();
+    }
+    else
+    {
+        MS_PUSH(fMachineState);
+        fMachineState = kIOPM_NotifyChildrenStart;
+        PM_LOG2("%s: %u outstanding async interest\n",
+            getName(), fHeadNotePendingAcks);
     }
-    return IOPMWillAckLater;                            // they didn't
 }
 
-
 //*********************************************************************************
-// parent_down_02
-//
-// All priority kernel clients have been notified of a power lowering
-// initiated by the parent and we didn't have to wait for any responses.  Here
-// we notify any interested drivers and power domain children.  If they all ack,
-// we continue with the power change.
-// If at least one doesn't, we have to wait for it to acknowledge and then continue.
+// [private] notifyChildren
 //*********************************************************************************
 
-IOReturn IOService::parent_down_02 ( void )
+void IOService::notifyChildren ( void )
 {
-    priv->machine_state = IOPMparent_down_4;            // in case they don't all ack
-    if ( notifyAll(true) == IOPMAckImplied ) {
-        return parent_down_1();                         // they did
+    OSIterator *               iter;
+    OSObject *                 next;
+    IOPowerConnection *        connection;
+       OSArray *                       children = 0;
+    IOPMrootDomain *    rootDomain;
+    bool                delayNotify = false;
+    
+    if ((fHeadNotePowerState != fCurrentPowerState) &&
+        (IS_POWER_DROP == fIsPreChange) &&
+        ((rootDomain = getPMRootDomain()) == this))
+    {
+        rootDomain->tracePoint( IS_POWER_DROP ?
+            kIOPMTracePointSleepPowerPlaneDrivers :
+            kIOPMTracePointWakePowerPlaneDrivers  );
     }
-    return IOPMWillAckLater;                            // they didn't
-}
 
+       if (fStrictTreeOrder)
+               children = OSArray::withCapacity(8);
 
-//*********************************************************************************
-// parent_down_04
-//
-// All applications and kernel clients have been notified of a power lowering
-// initiated by the parent and we had to wait for responses.  Here
-// we notify any priority clients.  If they all ack, we continue with the power change.
-// If at least one doesn't, we have to wait for it to acknowledge and then continue.
-//*********************************************************************************
+    // Sum child power consumption in notifyChild()
+    fHeadNotePowerArrayEntry->staticPower = 0;
 
-void IOService::parent_down_04 ( void )
-{
-    priv->machine_state = IOPMparent_down_05;           // in case they don't all ack
-    if ( tellChangeDown2(priv->head_note_state) ) {    // are we waiting for responses?
-        parent_down_05();                              // no, notify interested drivers
+    iter = getChildIterator(gIOPowerPlane);
+    if ( iter )
+    {
+        while ((next = iter->getNextObject()))
+        {
+            if ((connection = OSDynamicCast(IOPowerConnection, next)))
+            {
+                               if (connection->getReadyFlag() == false)
+                               {
+                                       PM_LOG3("[%s] %s: connection not ready\n",
+                                               getName(), __FUNCTION__);
+                                       continue;
+                               }
+
+                // Mechanism to postpone the did-change notification to
+                // certain power children to order those children last.
+                // Cannot be used together with strict tree ordering.
+
+                if (!fIsPreChange &&
+                    (connection->delayChildNotification) &&
+                    getPMRootDomain()->shouldDelayChildNotification(this))
+                {
+                    if (!children)
+                    {
+                        children = OSArray::withCapacity(8);
+                        if (children)
+                            delayNotify = true;
+                    }
+                    if (delayNotify)
+                    {
+                        children->setObject( connection );
+                        continue;
+                    }
+                }
+
+                               if (!delayNotify && children)
+                                       children->setObject( connection );
+                               else
+                                       notifyChild( connection );
+                       }
+        }
+        iter->release();
     }
-}
 
+    if (children && (children->getCount() == 0))
+    {
+        children->release();
+        children = 0;
+    }
+       if (children)
+       {
+        assert(fNotifyChildArray == 0);
+        fNotifyChildArray = children;        
+        MS_PUSH(fMachineState);
+
+        if (delayNotify)
+        {
+            // Wait for exiting child notifications to complete,
+            // before notifying the children in the array.
+            fMachineState = kIOPM_NotifyChildrenDelayed;
+            PM_LOG2("%s: %d children in delayed array\n",
+                getName(), children->getCount());
+        }
+        else
+        {
+            // Notify children in the array one at a time.
+            fMachineState = kIOPM_NotifyChildrenOrdered;
+        }
+       }
+}
 
 //*********************************************************************************
-// parent_down_05
-//
-// All applications and kernel clients have been notified of a power lowering
-// initiated by the parent and we had to wait for their responses.  Here we notify
-// any interested drivers and power domain children.  If they all ack, we continue
-// with the power change.
-// If at least one doesn't, we have to wait for it to acknowledge and then continue.
+// [private] notifyChildrenOrdered
 //*********************************************************************************
 
-void IOService::parent_down_05 ( void )
+void IOService::notifyChildrenOrdered ( void )
 {
-    priv->machine_state = IOPMparent_down_4;            // in case they don't all ack
-    if ( notifyAll(true) == IOPMAckImplied ) {
-        parent_down_4();                                // they did
-    }
-}
+       PM_ASSERT_IN_GATE();
+       assert(fNotifyChildArray);
+       assert(fMachineState == kIOPM_NotifyChildrenOrdered);
+
+       // Notify one child, wait for it to ack, then repeat for next child.
+       // This is a workaround for some drivers with multiple instances at
+       // the same branch in the power tree, but the driver is slow to power
+       // up unless the tree ordering is observed. Problem observed only on
+       // system wake, not on system sleep.
+       //
+       // We have the ability to power off in reverse child index order.
+       // That works nicely on some machines, but not on all HW configs.
+
+       if (fNotifyChildArray->getCount())
+       {
+               IOPowerConnection *     connection;
+               connection = (IOPowerConnection *) fNotifyChildArray->getObject(0);
+               fNotifyChildArray->removeObject(0);
+               notifyChild( connection );
+       }
+       else
+       {
+               fNotifyChildArray->release();
+               fNotifyChildArray = 0;
 
+        MS_POP();   // pushed by notifyChildren()
+       }
+}
 
 //*********************************************************************************
-// parent_down_1
-//
-// All parties have acknowledged our pre-change notification of a power
-// lowering initiated by the parent.  Here we instruct our controlling driver
-// to put the hardware in the state it needs to be in when the domain is
-// lowered.  If it does so, we continue processing
-// (waiting for settle and acknowledging the parent.)
-// If it doesn't, we have to wait for it to acknowledge and then continue.
+// [private] notifyChildrenDelayed
 //*********************************************************************************
 
-IOReturn IOService::parent_down_1 ( void )
+void IOService::notifyChildrenDelayed ( void )
 {
-    if ( instruct_driver(priv->head_note_state) == IOPMAckImplied ) {
-        return parent_down_2();                        // it's done, carry on
-    }
-    priv->machine_state = IOPMparent_down_5;   // it's not, wait for it
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogStartAckTimer,0,0);
-    start_ack_timer();
-    return IOPMWillAckLater;
-}
+    IOPowerConnection *        connection;
 
+       PM_ASSERT_IN_GATE();
+       assert(fNotifyChildArray);
+       assert(fMachineState == kIOPM_NotifyChildrenDelayed);
 
-//*********************************************************************************
-// parent_down_4
-//
-// We had to wait for it, but all parties have acknowledged our pre-change
-// notification of a power lowering initiated by the parent.
-// Here we instruct our controlling driver
-// to put the hardware in the state it needs to be in when the domain is
-// lowered.  If it does so, we continue processing
-// (waiting for settle and acknowledging the parent.)
-// If it doesn't, we have to wait for it to acknowledge and then continue.
-//*********************************************************************************
+    // Wait after all non-delayed children and interested drivers have ack'ed,
+    // then notify all delayed children. When explicitly cancelled, interest
+    // acks (and ack timer) may still be outstanding.
 
-void IOService::parent_down_4 ( void )
-{
-    if ( instruct_driver(priv->head_note_state) == IOPMAckImplied ) {
-        parent_down_5();                                       // it's done, carry on
-    }
-    else {
-        priv-> machine_state = IOPMparent_down_5;      // it's not, wait for it
-        pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogStartAckTimer,0,0);
-        start_ack_timer();
+    for (int i = 0; ; i++)
+    {
+               connection = (IOPowerConnection *) fNotifyChildArray->getObject(i);
+        if (!connection)
+            break;
+
+               notifyChild( connection );
     }
-}
 
+    PM_LOG2("%s: notified delayed children\n", getName());
+    fNotifyChildArray->release();
+    fNotifyChildArray = 0;
+    
+    MS_POP();   // pushed by notifyChildren()
+}
 
 //*********************************************************************************
-// parent_down_2
-//
-// Our controlling driver has changed power state on the hardware
-// during a power change initiated by our parent.  Here we see if we need
-// to wait for power to settle before continuing.  If not, we continue
-// processing (acknowledging our preparedness to the parent).
-// If so, we wait and continue later.
+// [private] notifyAll
 //*********************************************************************************
 
-IOReturn IOService::parent_down_2 ( void )
+IOReturn IOService::notifyAll ( uint32_t nextMS )
 {
-    IOService * nub;
-    
-    priv->settle_time = compute_settle_time();
-    if ( priv->settle_time == 0 ) {
-        priv->machine_state = IOPMparent_down_6;       // in case they don't all ack
-        if ( notifyAll(false) == IOPMAckImplied ) {
-            nub = priv->head_note_parent;
-            all_done();
-            nub->release();
-            return IOPMAckImplied;
-        }
-        return IOPMWillAckLater;                       // they didn't
-   }
-   else {
-       priv->machine_state = IOPMparent_down_3;
-       startSettleTimer(priv->settle_time);
-       return IOPMWillAckLater;
-   }
-}
+       // Save the next machine_state to be restored by notifyInterestedDriversDone()
+
+       PM_ASSERT_IN_GATE();
+    MS_PUSH(nextMS);
+       fMachineState     = kIOPM_DriverThreadCallDone;
+       fDriverCallReason = fIsPreChange ?
+                                               kDriverCallInformPreChange : kDriverCallInformPostChange;
 
+       if (!notifyInterestedDrivers())
+               notifyInterestedDriversDone();
+
+       return IOPMWillAckLater;
+}
 
 //*********************************************************************************
-// parent_down_5
+// [private, static] pmDriverCallout
 //
-// Our controlling driver has changed power state on the hardware
-// during a power change initiated by our parent.  We have had to wait
-// for acknowledgement from interested parties, or we have had to wait
-// for the controlling driver to change the state.  Here we see if we need
-// to wait for power to settle before continuing.  If not, we continue
-// processing (acknowledging our preparedness to the parent).
-// If so, we wait and continue later.
+// Thread call context
 //*********************************************************************************
 
-void IOService::parent_down_5 ( void )
+IOReturn IOService::actionDriverCalloutDone (
+       OSObject * target,
+       void * arg0, void * arg1,
+       void * arg2, void * arg3 )
 {
-    priv->settle_time = compute_settle_time();
-    if ( priv->settle_time == 0 ) {
-        parent_down_3();
-   }
-   else {
-       priv->machine_state = IOPMparent_down_3;
-       startSettleTimer(priv->settle_time);
-   }
+    IOServicePM * pwrMgt = (IOServicePM *) arg0;
+
+    assert( fDriverCallBusy );
+    fDriverCallBusy = false;
+
+    assert(gIOPMWorkQueue);
+    gIOPMWorkQueue->signalWorkAvailable();
+
+    return kIOReturnSuccess;
 }
 
+void IOService::pmDriverCallout ( IOService * from )
+{
+       assert(from);
+       switch (from->fDriverCallReason)
+       {
+               case kDriverCallSetPowerState:
+                       from->driverSetPowerState();
+                       break;
+
+               case kDriverCallInformPreChange:
+               case kDriverCallInformPostChange:
+                       from->driverInformPowerChange();
+                       break;
+
+               default:
+                       panic("IOService::pmDriverCallout bad machine state %x",
+                from->fDriverCallReason);
+       }
+
+       gIOPMWorkLoop->runAction(actionDriverCalloutDone,
+               /* target */ from,
+               /* arg0   */ (void *) from->pwrMgt );
+}
 
 //*********************************************************************************
-// parent_down_3
+// [private] driverSetPowerState
 //
-// Power has settled on a power change initiated by our parent.  Here we
-// notify interested parties.
+// Thread call context
 //*********************************************************************************
 
-void IOService::parent_down_3 ( void )
+void IOService::driverSetPowerState ( void )
 {
-    IORegistryEntry *  nub;
-    IOService *        parent;
-
-    priv->machine_state = IOPMparent_down_6;   // in case they don't all ack
-    if ( notifyAll(false) == IOPMAckImplied ) {
-        nub = priv->head_note_parent;
-        all_done();
-        parent = (IOService *)nub->copyParentEntry(gIOPowerPlane);
-        if ( parent ) {
-            parent->acknowledgePowerChange((IOService *)nub);
-            parent->release();
+    IOPMPowerStateIndex powerState;
+    DriverCallParam *  param;
+    IOPMDriverCallEntry callEntry;
+    AbsoluteTime        end;
+    IOReturn            result;
+    uint32_t            oldPowerState = getPowerState();
+
+    assert( fDriverCallBusy );
+    assert( fDriverCallParamPtr );
+    assert( fDriverCallParamCount == 1 );
+
+    param = (DriverCallParam *) fDriverCallParamPtr;
+    powerState = fHeadNotePowerState;
+
+    if (assertPMDriverCall(&callEntry))
+    {
+        OUR_PMLog(          kPMLogProgramHardware, (uintptr_t) this, powerState);
+        clock_get_uptime(&fDriverCallStartTime);
+        result = fControllingDriver->setPowerState( powerState, this );
+        clock_get_uptime(&end);
+        OUR_PMLog((UInt32) -kPMLogProgramHardware, (uintptr_t) this, (UInt32) result);
+
+        deassertPMDriverCall(&callEntry);
+
+        if (result < 0)
+        {
+            PM_LOG("%s::setPowerState(%p, %lu -> %lu) returned 0x%x\n",
+                fName, this, fCurrentPowerState, powerState, result);
+        }
+
+#if LOG_SETPOWER_TIMES
+        if ((result == IOPMAckImplied) || (result < 0))
+        {
+            uint64_t    nsec;
+
+            SUB_ABSOLUTETIME(&end, &fDriverCallStartTime);
+            absolutetime_to_nanoseconds(end, &nsec);
+            if (nsec > LOG_SETPOWER_TIMES)
+                PM_LOG("%s::setPowerState(%p, %lu -> %lu) took %d ms\n",
+                    fName, this, fCurrentPowerState, powerState, NS_TO_MS(nsec));
+
+            PMEventDetails *details = PMEventDetails::eventDetails(
+                                        kIOPMEventTypeSetPowerStateImmediate, // type
+                                        fName,                                                           // who
+                                        (uintptr_t)this,                                         // owner unique
+                                        NULL,                                                            // interest name
+                                        (uint8_t)oldPowerState,                                  // old
+                                        (uint8_t)powerState,                             // new
+                                        0,                                                                       // result
+                                        NS_TO_US(nsec));                                         // usec completion time
+
+            getPMRootDomain()->recordAndReleasePMEventGated( details );
         }
-        nub->release();
+#endif
     }
-}
+    else
+        result = kIOPMAckImplied;
 
+    param->Result = result;
+}
 
 //*********************************************************************************
-// parent_down_6
+// [private] driverInformPowerChange
 //
-// We had to wait for it, but all parties have acknowledged our post-change
-// notification of a power  lowering initiated by the parent.
-// Here we acknowledge the parent.
-// We are done with this change note, and we can start on the next one.
+// Thread call context
 //*********************************************************************************
 
-void IOService::parent_down_6 ( void )
+void IOService::driverInformPowerChange ( void )
 {
-    IORegistryEntry *  nub;
-    IOService *                parent;
+    IOPMinformee *             informee;
+    IOService *                        driver;
+    DriverCallParam *  param;
+    IOPMDriverCallEntry callEntry;
+    IOPMPowerFlags             powerFlags;
+    IOPMPowerStateIndex powerState;
+    AbsoluteTime        end;
+    IOReturn            result;
+    IOItemCount                        count;
+
+    assert( fDriverCallBusy );
+    assert( fDriverCallParamPtr );
+    assert( fDriverCallParamCount );
+
+    param = (DriverCallParam *) fDriverCallParamPtr;
+    count = fDriverCallParamCount;
+
+    powerFlags = fHeadNotePowerArrayEntry->capabilityFlags;
+    powerState = fHeadNotePowerState;
+
+    for (IOItemCount i = 0; i < count; i++)
+    {
+        informee = (IOPMinformee *) param->Target;
+        driver   = informee->whatObject;
+
+        if (assertPMDriverCall(&callEntry, 0, informee))
+        {
+            if (fDriverCallReason == kDriverCallInformPreChange)
+            {
+                OUR_PMLog(kPMLogInformDriverPreChange, (uintptr_t) this, powerState);
+                clock_get_uptime(&informee->startTime);
+                result = driver->powerStateWillChangeTo(powerFlags, powerState, this);
+                clock_get_uptime(&end);
+                OUR_PMLog((UInt32)-kPMLogInformDriverPreChange, (uintptr_t) this, result);
+            }
+            else
+            {
+                OUR_PMLog(kPMLogInformDriverPostChange, (uintptr_t) this, powerState);
+                clock_get_uptime(&informee->startTime);
+                result = driver->powerStateDidChangeTo(powerFlags, powerState, this);
+                clock_get_uptime(&end);
+                OUR_PMLog((UInt32)-kPMLogInformDriverPostChange, (uintptr_t) this, result);
+            }
     
-    nub = priv->head_note_parent;
-    all_done();
-    parent = (IOService *)nub->copyParentEntry(gIOPowerPlane);
-    if ( parent ) {
-        parent->acknowledgePowerChange((IOService *)nub);
-        parent->release();
+            deassertPMDriverCall(&callEntry);
+
+#if LOG_SETPOWER_TIMES
+            if ((result == IOPMAckImplied) || (result < 0))
+            {
+                uint64_t nsec;
+
+                SUB_ABSOLUTETIME(&end, &informee->startTime);
+                absolutetime_to_nanoseconds(end, &nsec);
+                if (nsec > LOG_SETPOWER_TIMES)
+                    PM_LOG("%s::powerState%sChangeTo(%p, %s, %lu -> %lu) took %d ms\n",
+                        driver->getName(),
+                        (fDriverCallReason == kDriverCallInformPreChange) ? "Will" : "Did",
+                        driver, fName, fCurrentPowerState, powerState, NS_TO_MS(nsec));
+
+                uint16_t logType = (fDriverCallReason == kDriverCallInformPreChange) 
+                                    ? kIOPMEventTypePSWillChangeTo
+                                    : kIOPMEventTypePSDidChangeTo;
+
+                PMEventDetails *details = PMEventDetails::eventDetails(
+                                            logType,                                           // type
+                                            fName,                                                     // who
+                                            (uintptr_t)this,                           // owner unique
+                                            driver->getName(),                         // interest name
+                                            (uint8_t)fCurrentPowerState,       // old
+                                            (uint8_t)fHeadNotePowerState,      // new
+                                            0,                                                         // result
+                                            NS_TO_US(nsec));                           // usec completion time
+
+                getPMRootDomain()->recordAndReleasePMEventGated( details );
+            }
+#endif
+        }
+        else
+            result = kIOPMAckImplied;
+
+        param->Result = result;
+        param++;
     }
-    nub->release();
 }
 
-
 //*********************************************************************************
-// parent_up_0
+// [private] notifyChild
 //
-// Our parent has informed us via powerStateDidChange that it has
-// raised the power in our power domain, and we have had to wait
-// for some interested party to acknowledge our notification.
-//   Here we instruct our controlling
-// driver to program the hardware to take advantage of the higher domain
-// power.  If it does so, we continue processing
-// (waiting for settle and notifying interested parties post-change.)
-// If it doesn't, we have to wait for it to acknowledge and then continue.
+// Notify a power domain child of an upcoming power change.
+// If the object acknowledges the current change, we return TRUE.
 //*********************************************************************************
 
-void IOService::parent_up_0 ( void )
+bool IOService::notifyChild ( IOPowerConnection * theNub )
 {
-    if ( instruct_driver(priv->head_note_state) == IOPMAckImplied ) {
-        parent_up_4();                                 // it did it, carry on
+    IOReturn                ret = IOPMAckImplied;
+    unsigned long           childPower;
+    IOService *             theChild;
+       IOPMRequest *           childRequest;
+    IOPMPowerChangeFlags    requestArg2;
+       int                     requestType;
+
+       PM_ASSERT_IN_GATE();
+    theChild = (IOService *)(theNub->copyChildEntry(gIOPowerPlane));
+    if (!theChild)
+    {
+               assert(false);
+        return true;
     }
-    else {
-        priv->machine_state = IOPMparent_up_4; // it didn't, wait for it
-        pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogStartAckTimer,0,0);
-        start_ack_timer();
+
+    // Unless the child handles the notification immediately and returns
+    // kIOPMAckImplied, we'll be awaiting their acknowledgement later.
+       fHeadNotePendingAcks++;
+    theNub->setAwaitingAck(true);
+
+    requestArg2 = fHeadNoteChangeFlags;
+    if (fHeadNotePowerState < fCurrentPowerState)
+        requestArg2 |= kIOPMDomainPowerDrop;
+
+    requestType = fIsPreChange ?
+        kIOPMRequestTypePowerDomainWillChange :
+        kIOPMRequestTypePowerDomainDidChange;
+
+       childRequest = acquirePMRequest( theChild, requestType );
+       if (childRequest)
+       {
+        theNub->retain();
+               childRequest->fArg0 = (void *) fHeadNotePowerArrayEntry->outputPowerFlags;
+               childRequest->fArg1 = (void *) theNub;
+               childRequest->fArg2 = (void *) requestArg2;
+               theChild->submitPMRequest( childRequest );
+               ret = IOPMWillAckLater;
+       }
+       else
+       {
+               ret = IOPMAckImplied;
+               fHeadNotePendingAcks--;  
+               theNub->setAwaitingAck(false);
+        childPower = theChild->currentPowerConsumption();
+        if ( childPower == kIOPMUnknown )
+        {
+            fHeadNotePowerArrayEntry->staticPower = kIOPMUnknown;
+        } else {
+            if (fHeadNotePowerArrayEntry->staticPower != kIOPMUnknown )
+                fHeadNotePowerArrayEntry->staticPower += childPower;
+        }
     }
-}
 
+    theChild->release();
+       return (IOPMAckImplied == ret);
+}
 
 //*********************************************************************************
-// parent_up_1
-//
-// Our parent has informed us via powerStateDidChange that it has
-// raised the power in our power domain.  Here we instruct our controlling
-// driver to program the hardware to take advantage of the higher domain
-// power.  If it does so, we continue processing
-// (waiting for settle and notifying interested parties post-change.)
-// If it doesn't, we have to wait for it to acknowledge and then continue.
+// [private] notifyControllingDriver
 //*********************************************************************************
 
-IOReturn IOService::parent_up_1 ( void )
+bool IOService::notifyControllingDriver ( void )
 {
-    if ( instruct_driver(priv->head_note_state) == IOPMAckImplied ) {
-        return parent_up_2();                          // it did it, carry on
+    DriverCallParam *  param;
+
+    PM_ASSERT_IN_GATE();
+    assert( fDriverCallParamCount == 0  );
+    assert( fControllingDriver );
+
+    if (fInitialSetPowerState)
+    {
+        // Driver specified flag to skip the inital setPowerState()
+        if (fHeadNotePowerArrayEntry->capabilityFlags & kIOPMInitialDeviceState)
+        {
+            return false;
+        }
+        fInitialSetPowerState = false;
     }
-    else {
-        priv->machine_state = IOPMparent_up_4; // it didn't, wait for it
-        pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogStartAckTimer,0,0);
-        start_ack_timer();
-        return IOPMWillAckLater;
+
+    param = (DriverCallParam *) fDriverCallParamPtr;
+    if (!param)
+    {
+        param = IONew(DriverCallParam, 1);
+        if (!param)
+            return false;      // no memory
+
+        fDriverCallParamPtr   = (void *) param;
+        fDriverCallParamSlots = 1;
     }
-}
 
+    param->Target = fControllingDriver;
+    fDriverCallParamCount = 1;
+    fDriverTimer = -1;
 
-//*********************************************************************************
-// parent_up_2
-//
-// Our controlling driver has changed power state on the hardware
-// during a power raise initiated by the parent.  Here we see if we need to wait
-// for power to settle before continuing.  If not, we continue processing
-// (notifying interested parties post-change).  If so, we wait and
-// continue later.
-//*********************************************************************************
+    // Block state machine and wait for callout completion.
+    assert(!fDriverCallBusy);
+    fDriverCallBusy = true;
+    thread_call_enter( fDriverCallEntry );
 
-IOReturn IOService::parent_up_2 ( void )
-{
-    priv->settle_time = compute_settle_time();
-    if ( priv->settle_time == 0 ) {
-        return parent_up_3();
-  }
-  else {
-      priv->machine_state = IOPMparent_up_5;
-      startSettleTimer(priv->settle_time);
-      return IOPMWillAckLater;
-  }
+    return true;
 }
 
-
 //*********************************************************************************
-// parent_up_4
-//
-// Our controlling driver has changed power state on the hardware
-// during a power raise initiated by the parent, but we had to wait for it.
-// Here we see if we need to wait for power to settle before continuing.
-// If not, we continue processing  (notifying interested parties post-change).
-// If so, we wait and continue later.
+// [private] notifyControllingDriverDone
 //*********************************************************************************
 
-void IOService::parent_up_4 ( void )
+void IOService::notifyControllingDriverDone( void )
 {
-    priv->settle_time = compute_settle_time();
-    if ( priv->settle_time == 0 ) {
-        parent_up_5();
-  }
-  else {
-      priv->machine_state = IOPMparent_up_5;
-      startSettleTimer(priv->settle_time);
-  }
-}
+       DriverCallParam *       param;
+       IOReturn                        result;
+
+       PM_ASSERT_IN_GATE();
+       param = (DriverCallParam *) fDriverCallParamPtr;
+
+       assert( fDriverCallBusy == false );
+       assert( fMachineState == kIOPM_DriverThreadCallDone );
+
+       if (param && fDriverCallParamCount)
+       {
+               assert(fDriverCallParamCount == 1);
+               
+               // the return value from setPowerState()
+               result = param->Result;
+
+               if ((result == IOPMAckImplied) || (result < 0))
+               {
+            fDriverTimer = 0;
+               }
+               else if (fDriverTimer)
+               {
+            assert(fDriverTimer == -1);
+
+            // Driver has not acked, and has returned a positive result.
+            // Enforce a minimum permissible timeout value.
+            // Make the min value large enough so timeout is less likely
+            // to occur if a driver misinterpreted that the return value
+            // should be in microsecond units.  And make it large enough
+            // to be noticeable if a driver neglects to ack.
+
+            if (result < kMinAckTimeoutTicks)
+                result = kMinAckTimeoutTicks;
+
+            fDriverTimer = (result / (ACK_TIMER_PERIOD / ns_per_us)) + 1;
+               }
+               // else, child has already acked and driver_timer reset to 0.
+
+               fDriverCallParamCount = 0;
+
+               if ( fDriverTimer )
+               {
+                       OUR_PMLog(kPMLogStartAckTimer, 0, 0);
+                       start_ack_timer();
+               }
+       }
 
+    MS_POP();   // pushed by OurChangeSetPowerState()
+    fIsPreChange  = false;
+}
 
 //*********************************************************************************
-// parent_up_3
+// [private] all_done
 //
-// No power settling was required on a power raise initiated by the parent.
-// Here we notify all our interested parties post-change.  If they all acknowledge,
-// we're done with this change note, and we can start on the next one.
-// Otherwise we have to wait for acknowledgements and finish up later.
+// A power change is done.
 //*********************************************************************************
 
-IOReturn IOService::parent_up_3 ( void )
+void IOService::all_done ( void )
 {
-    IOService * nub;
-    
-    priv->machine_state = IOPMparent_up_6;     // in case they don't all ack
-    if ( notifyAll(false) == IOPMAckImplied ) {
-        nub = priv->head_note_parent;
-        all_done();
-        nub->release();
-        return IOPMAckImplied;
+    IOPMPowerStateIndex     prevPowerState;
+    const IOPMPSEntry *     powerStatePtr;
+    IOPMDriverCallEntry     callEntry;
+    uint32_t                prevMachineState = fMachineState;
+    bool                    callAction = false;
+
+    fMachineState = kIOPM_Finished;
+
+    if ((fHeadNoteChangeFlags & kIOPMSynchronize) &&
+        ((prevMachineState == kIOPM_Finished) ||
+         (prevMachineState == kIOPM_SyncFinish)))
+    {
+        // Sync operation and no power change occurred.
+        // Do not inform driver and clients about this request completion,
+        // except for the originator (root domain).
+
+        PM_ACTION_2(actionPowerChangeDone,
+            fHeadNotePowerState, fHeadNoteChangeFlags);
+
+        if (getPMRequestType() == kIOPMRequestTypeSynchronizePowerTree)
+        {
+            powerChangeDone(fCurrentPowerState);
+        }
+
+        return;
     }
-    return IOPMWillAckLater;                   // they didn't
-}
 
+    // our power change
+    if ( fHeadNoteChangeFlags & kIOPMSelfInitiated )
+    {
+        // could our driver switch to the new state?
+        if ( !( fHeadNoteChangeFlags & kIOPMNotDone) )
+        {
+                       // we changed, tell our parent
+            requestDomainPower(fHeadNotePowerState);
+
+            // yes, did power raise?
+            if ( fCurrentPowerState < fHeadNotePowerState )
+            {
+                // yes, inform clients and apps
+                tellChangeUp (fHeadNotePowerState);
+            }
+            prevPowerState = fCurrentPowerState;
+            // either way
+            fCurrentPowerState = fHeadNotePowerState;
+#if PM_VARS_SUPPORT
+            fPMVars->myCurrentState = fCurrentPowerState;
+#endif
+            OUR_PMLog(kPMLogChangeDone, fCurrentPowerState, 0);
+            PM_ACTION_2(actionPowerChangeDone,
+                fHeadNotePowerState, fHeadNoteChangeFlags);
+            callAction = true;
+
+            powerStatePtr = &fPowerStates[fCurrentPowerState];
+            fCurrentCapabilityFlags = powerStatePtr->capabilityFlags;
+            if (fCurrentCapabilityFlags & kIOPMStaticPowerValid)
+                fCurrentPowerConsumption = powerStatePtr->staticPower;
+
+            // inform subclass policy-maker
+            if (fPCDFunctionOverride && fParentsKnowState &&
+                assertPMDriverCall(&callEntry, kIOPMADC_NoInactiveCheck))
+            {
+                powerChangeDone(prevPowerState);
+                deassertPMDriverCall(&callEntry);
+            }
+        }
+        else if (getPMRequestType() == kIOPMRequestTypeRequestPowerStateOverride)
+        {
+            // changePowerStateWithOverrideTo() was cancelled
+            fOverrideMaxPowerState = kIOPMPowerStateMax;
+        }
+    }
 
-//*********************************************************************************
-// parent_up_5
-//
-// Power has settled on a power raise initiated by the parent.
-// Here we notify all our interested parties post-change.  If they all acknowledge,
-// we're done with this change note, and we can start on the next one.
-// Otherwise we have to wait for acknowledgements and finish up later.
-//*********************************************************************************
+    // parent's power change
+    if ( fHeadNoteChangeFlags & kIOPMParentInitiated)
+    {
+        if (((fHeadNoteChangeFlags & kIOPMDomainWillChange) &&
+             (fCurrentPowerState >= fHeadNotePowerState))   ||
+                         ((fHeadNoteChangeFlags & kIOPMDomainDidChange)  &&
+             (fCurrentPowerState < fHeadNotePowerState)))
+        {
+            if ((fHeadNoteChangeFlags & kIOPMPowerSuppressed) &&
+                (fHeadNotePowerState != fCurrentPowerState) &&
+                (fHeadNotePowerState == fDesiredPowerState))
+            {
+                // Power changed, and desired power state restored.
+                // Clear any prior power desire while in suppressed state.
+                requestDomainPower(fHeadNotePowerState);
+            }
 
-void IOService::parent_up_5 ( void )
-{
-    priv->machine_state = IOPMparent_up_6;     // in case they don't all ack
-    if ( notifyAll(false) == IOPMAckImplied ) {
-        parent_up_6();
+            // did power raise?
+            if ( fCurrentPowerState < fHeadNotePowerState )
+            {
+                // yes, inform clients and apps
+                tellChangeUp (fHeadNotePowerState);
+            }
+            // either way
+            prevPowerState = fCurrentPowerState;
+            fCurrentPowerState = fHeadNotePowerState;
+#if PM_VARS_SUPPORT
+            fPMVars->myCurrentState = fCurrentPowerState;
+#endif
+            fMaxPowerState = fControllingDriver->maxCapabilityForDomainState(fHeadNoteDomainFlags);
+
+            OUR_PMLog(kPMLogChangeDone, fCurrentPowerState, 0);
+            PM_ACTION_2(actionPowerChangeDone,
+                fHeadNotePowerState, fHeadNoteChangeFlags);
+            callAction = true;
+
+            powerStatePtr = &fPowerStates[fCurrentPowerState];
+            fCurrentCapabilityFlags = powerStatePtr->capabilityFlags;
+            if (fCurrentCapabilityFlags & kIOPMStaticPowerValid)
+                fCurrentPowerConsumption = powerStatePtr->staticPower;
+
+            // inform subclass policy-maker
+            if (fPCDFunctionOverride && fParentsKnowState &&
+                assertPMDriverCall(&callEntry, kIOPMADC_NoInactiveCheck))
+            {
+                powerChangeDone(prevPowerState);
+                deassertPMDriverCall(&callEntry);
+            }
+        }
     }
-}
 
+    // When power rises enough to satisfy the tickle's desire for more power,
+    // the condition preventing idle-timer from dropping power is removed.
 
-//*********************************************************************************
-// parent_up_6
-//
-// All parties have acknowledged our post-change notification of a power
-// raising initiated by the parent.  Here we acknowledge the parent.
-// We are done with this change note, and we can start on the next one.
-//*********************************************************************************
+    if (fCurrentPowerState >= fIdleTimerMinPowerState)
+    {
+        fIdleTimerMinPowerState = 0;
+    }
 
-void IOService::parent_up_6 ( void )
-{
-    IORegistryEntry *  nub;
-    IOService *                parent;
-    
-    nub = priv->head_note_parent;
-    all_done();
-    parent = (IOService *)nub->copyParentEntry(gIOPowerPlane);
-    if ( parent ) {
-        parent->acknowledgePowerChange((IOService *)nub);
-        parent->release();
+    if (!callAction)
+    {
+        PM_ACTION_2(actionPowerChangeDone,
+            fHeadNotePowerState, fHeadNoteChangeFlags);
     }
-    nub->release();
 }
 
+// MARK: -
+// MARK: Power Change Initiated by Driver
 
 //*********************************************************************************
-// all_done
+// [private] OurChangeStart
 //
-// A power change is complete, and the used post-change note is at
-// the head of the queue.  Remove it and set myCurrentState to the result
-// of the change.  Start up the next change in queue.
+// Begin the processing of a power change initiated by us.
 //*********************************************************************************
 
-void IOService::all_done ( void )
+void IOService::OurChangeStart ( void )
 {
-    unsigned long      previous_state;
-    IORegistryEntry *  nub;
-    IOService *                parent;
-    
-    priv->machine_state = IOPMfinished;
+       PM_ASSERT_IN_GATE();
+    OUR_PMLog( kPMLogStartDeviceChange, fHeadNotePowerState, fCurrentPowerState );
 
-    if ( priv->head_note_flags & IOPMWeInitiated ) {                           // our power change
-        if ( !( priv->head_note_flags & IOPMNotDone) ) {                       // could our driver switch to the new state?
-            if ( pm_vars->myCurrentState < priv->head_note_state ) {           // yes, did power raise?
-                tellChangeUp (priv->head_note_state);                          // yes, inform clients and apps
-            }
-            else {
-                if ( !  priv->we_are_root ) {                                  // no, if this lowers our
-                    ask_parent(priv->head_note_state);                         // power requirements, tell the parent
-                }
-            }
-            previous_state = pm_vars->myCurrentState;
-            pm_vars->myCurrentState = priv->head_note_state;                   // either way
-            priv->imminentState = pm_vars->myCurrentState;
-            pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogChangeDone,(unsigned long)pm_vars->myCurrentState,0);
-            powerChangeDone(previous_state);                                   // inform subclass policy-maker
-        }
-//        else {                                                                       // no
-//            pm_vars->myCurrentState = pm_vars->theControllingDriver->powerStateForDomainState(pm_vars->parentsCurrentPowerFlags);
-//        }
-    }
-    if ( priv->head_note_flags & IOPMParentInitiated) {                                // parent's power change
-        if ( ((priv->head_note_flags & IOPMDomainWillChange) && (pm_vars->myCurrentState >= priv->head_note_state)) ||
-             ((priv->head_note_flags & IOPMDomainDidChange) && (pm_vars->myCurrentState < priv->head_note_state)) ) {
-            if ( pm_vars->myCurrentState < priv->head_note_state ) {           // did power raise?
-                tellChangeUp (priv->head_note_state);                          // yes, inform clients and apps
-            }
-            previous_state = pm_vars->myCurrentState;                          // either way
-            pm_vars->myCurrentState = priv->head_note_state;
-            priv->imminentState = pm_vars->myCurrentState;
-            pm_vars->maxCapability = pm_vars->theControllingDriver->maxCapabilityForDomainState(priv->head_note_domainState);
+       // fMaxPowerState is our maximum possible power state based on the current
+       // power state of our parents.  If we are trying to raise power beyond the
+       // maximum, send an async request for more power to all parents.
 
-            pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogChangeDone,(unsigned long)pm_vars->myCurrentState,0);
-            powerChangeDone(previous_state);                                   // inform subclass policy-maker
-        }
+    if (!IS_PM_ROOT && (fMaxPowerState < fHeadNotePowerState))
+    {
+        fHeadNoteChangeFlags |= kIOPMNotDone;
+        requestDomainPower(fHeadNotePowerState);
+        OurChangeFinish();
+        return;
     }
 
-    IOLockLock(priv->queue_lock);
-    priv->changeList->releaseHeadChangeNote();                                 // we're done with this
-        
-    priv->head_note = priv->changeList->currentChange();                       // start next one in queue
-    if ( priv->head_note != -1 ) {
+       // Redundant power changes skips to the end of the state machine.
 
-        IOLockUnlock(priv->queue_lock);
-        if (priv->changeList->changeNote[priv->head_note].flags & IOPMWeInitiated ) {
-            start_our_change(priv->head_note);
-        }
-        else {
-            nub = priv->changeList->changeNote[priv->head_note].parent;
-            if ( start_parent_change(priv->head_note) == IOPMAckImplied ) {
-                parent = (IOService *)nub->copyParentEntry(gIOPowerPlane);
-                if ( parent ) {
-                    parent->acknowledgePowerChange((IOService *)nub);
-                    parent->release();
-                }
-            }
-        }
+    if (!fInitialPowerChange && (fHeadNotePowerState == fCurrentPowerState))
+       {
+               OurChangeFinish();
+               return;
     }
-    IOLockUnlock(priv->queue_lock);
-}
+    fInitialPowerChange = false;
 
+    // Change started, but may not complete...
+    // Can be canceled (power drop) or deferred (power rise).
 
+    PM_ACTION_2(actionPowerChangeStart, fHeadNotePowerState, &fHeadNoteChangeFlags);
 
-//*********************************************************************************
-// all_acked
-//
-// A driver or child has acknowledged our notification of an upcoming power
-// change, and this acknowledgement is the last one pending
-// before we change power or after changing power.
-//
-//*********************************************************************************
+       // Two separate paths, depending if power is being raised or lowered.
+       // Lowering power is subject to approval by clients of this service.
 
-void IOService::all_acked ( void )
-{
-    switch (priv->machine_state) {
-       case IOPMour_prechange_1:
-           our_prechange_1();
-           break;
-       case IOPMour_prechange_4:
-           our_prechange_4();
-           break;
-       case IOPMparent_down_4:
-           parent_down_4();    
-           break;
-       case IOPMparent_down_6:
-           parent_down_6();
-           break;
-       case IOPMparent_up_0:
-           parent_up_0();
-           break;
-       case IOPMparent_up_6:
-           parent_up_6();
-           break;
-   }
-}
+    if (IS_POWER_DROP)
+    {
+        fDoNotPowerDown = false;
+
+        // Ask for persmission to drop power state
+        fMachineState = kIOPM_OurChangeTellClientsPowerDown;
+        fOutOfBandParameter = kNotifyApps;
+        askChangeDown(fHeadNotePowerState);
+    }
+       else
+       {
+        // This service is raising power and parents are able to support the
+        // new power state. However a parent may have already committed to
+        // drop power, which might force this object to temporarily drop power.
+        // This results in "oscillations" before the state machines converge
+        // to a steady state.
+        //
+        // To prevent this, a child must make a power reservation against all
+        // parents before raising power. If the reservation fails, indicating
+        // that the child will be unable to sustain the higher power state,
+        // then the child will signal the parent to adjust power, and the child
+        // will defer its power change.
+
+        IOReturn ret;
+
+        // Reserve parent power necessary to achieve fHeadNotePowerState.
+        ret = requestDomainPower( fHeadNotePowerState, kReserveDomainPower );
+        if (ret != kIOReturnSuccess)
+        {
+            // Reservation failed, defer power rise.
+            fHeadNoteChangeFlags |= kIOPMNotDone;
+            OurChangeFinish();
+            return;
+        }
 
+        OurChangeTellCapabilityWillChange();
+    }
+}
 
 //*********************************************************************************
-// settleTimerExpired
-//
-// Power has settled after our last change.  Notify interested parties that
-// there is a new power state.
-//*********************************************************************************
 
-void IOService::settleTimerExpired ( void )
+struct IOPMRequestDomainPowerContext {
+    IOService *     child;              // the requesting child
+    IOPMPowerFlags  requestPowerFlags;  // power flags requested by child
+};
+
+static void
+requestDomainPowerApplier(
+    IORegistryEntry *   entry,
+    void *              inContext )
 {
-    if ( ! initialized ) {
-        return;                                        // we're unloading
-    }
+    IOPowerConnection *             connection;
+    IOService *                     parent;
+    IOPMRequestDomainPowerContext * context;
 
-    switch (priv->machine_state) {
-        case IOPMour_prechange_3:
-            our_prechange_3();
-            break;
-        case IOPMparent_down_3:
-            parent_down_3();
-            break;
-        case IOPMparent_up_5:
-            parent_up_5();
-            break;
+    if ((connection = OSDynamicCast(IOPowerConnection, entry)) == 0)
+        return;
+    parent = (IOService *) connection->copyParentEntry(gIOPowerPlane);
+    if (!parent)
+        return;
+
+    assert(inContext);
+    context = (IOPMRequestDomainPowerContext *) inContext;
+
+    if (connection->parentKnowsState() && connection->getReadyFlag())
+    {
+        parent->requestPowerDomainState(
+            context->requestPowerFlags,
+            connection,
+            IOPMLowestState);
     }
-}
 
+    parent->release();
+}
 
 //*********************************************************************************
-// compute_settle_time
-//
-// Compute the power-settling delay in microseconds for the
-// change from myCurrentState to head_note_state.
+// [private] requestDomainPower
 //*********************************************************************************
 
-unsigned long IOService::compute_settle_time ( void )
+IOReturn IOService::requestDomainPower(
+    IOPMPowerStateIndex ourPowerState,
+    IOOptionBits        options )
 {
-    unsigned long totalTime;
-    unsigned long i;
+    const IOPMPSEntry *             powerStateEntry;
+    IOPMPowerFlags                  requestPowerFlags;
+    IOPMPowerStateIndex             maxPowerState;
+    IOPMRequestDomainPowerContext   context;
+
+       PM_ASSERT_IN_GATE();
+    assert(ourPowerState < fNumberOfPowerStates);
+    if (ourPowerState >= fNumberOfPowerStates)
+        return kIOReturnBadArgument;
+    if (IS_PM_ROOT)
+        return kIOReturnSuccess;
 
-    totalTime = 0;                                             // compute total time to attain the new state
-    i = pm_vars->myCurrentState;
-    if ( priv->head_note_state < pm_vars->myCurrentState ) {   // we're lowering power
-        while ( i > priv->head_note_state ) {
-            totalTime +=  pm_vars->thePowerStates[i].settleDownTime;
-            i--;
-        }
+    // Fetch the input power flags for the requested power state.
+    // Parent request is stated in terms of required power flags.
+
+       powerStateEntry = &fPowerStates[ourPowerState];
+       requestPowerFlags = powerStateEntry->inputPowerFlags;
+
+    if (powerStateEntry->capabilityFlags & (kIOPMChildClamp | kIOPMPreventIdleSleep))
+        requestPowerFlags |= kIOPMPreventIdleSleep;
+    if (powerStateEntry->capabilityFlags & (kIOPMChildClamp2 | kIOPMPreventSystemSleep))
+        requestPowerFlags |= kIOPMPreventSystemSleep;
+
+    // Disregard the "previous request" for power reservation.
+
+    if (((options & kReserveDomainPower) == 0) &&
+        (fPreviousRequestPowerFlags == requestPowerFlags))
+    {
+        // skip if domain already knows our requirements
+        goto done;
     }
+    fPreviousRequestPowerFlags = requestPowerFlags;
 
-    if ( priv->head_note_state > pm_vars->myCurrentState ) {   // we're raising power
-        while ( i < priv->head_note_state ) {
-            totalTime +=  pm_vars->thePowerStates[i+1].settleUpTime;
-            i++;
+    context.child              = this;
+    context.requestPowerFlags  = requestPowerFlags;
+    fHeadNoteDomainTargetFlags = 0;
+    applyToParents(requestDomainPowerApplier, &context, gIOPowerPlane);
+
+    if (options & kReserveDomainPower)
+    {
+        maxPowerState = fControllingDriver->maxCapabilityForDomainState(
+                            fHeadNoteDomainTargetFlags );
+
+        if (maxPowerState < fHeadNotePowerState)
+        {
+            PM_LOG1("%s: power desired %u:0x%x got %u:0x%x\n",
+                getName(),
+                (uint32_t) ourPowerState, (uint32_t) requestPowerFlags,
+                (uint32_t) maxPowerState, (uint32_t) fHeadNoteDomainTargetFlags);
+            return kIOReturnNoPower;
         }
     }
 
-    return totalTime;
+done:
+    return kIOReturnSuccess;
 }
 
-
 //*********************************************************************************
-// startSettleTimer
-//
-// Enter with a power-settling delay in microseconds and start a nano-second
-// timer for that delay.
+// [private] OurSyncStart
 //*********************************************************************************
 
-IOReturn IOService::startSettleTimer ( unsigned long delay )
+void IOService::OurSyncStart ( void )
 {
-    AbsoluteTime       deadline;
-    
-    clock_interval_to_deadline(delay, kMicrosecondScale, &deadline);
+       PM_ASSERT_IN_GATE();
 
-    thread_call_enter_delayed(priv->settleTimer, deadline);
+    if (fInitialPowerChange)
+        return;
 
-    return IOPMNoErr;
+    PM_ACTION_2(actionPowerChangeStart, fHeadNotePowerState, &fHeadNoteChangeFlags);
+
+    if (fHeadNoteChangeFlags & kIOPMNotDone)
+    {
+               OurChangeFinish();
+               return;
+    }
+
+    if (fHeadNoteChangeFlags & kIOPMSyncTellPowerDown)
+    {
+        fDoNotPowerDown = false;
+
+        // Ask for permission to drop power state
+        fMachineState = kIOPM_SyncTellClientsPowerDown;
+        fOutOfBandParameter = kNotifyApps;
+        askChangeDown(fHeadNotePowerState);
+    }
+    else
+    {
+        // Only inform capability app and clients.
+        tellSystemCapabilityChange( kIOPM_SyncNotifyWillChange );
+    }
 }
 
 //*********************************************************************************
-// ack_timer_ticked
+// [private] OurChangeTellClientsPowerDown
 //
-// The acknowledgement timeout periodic timer has ticked.
-// If we are awaiting acks for a power change notification,
-// we decrement the timer word of each interested driver which hasn't acked.
-// If a timer word becomes zero, we pretend the driver aknowledged.
-// If we are waiting for the controlling driver to change the power
-// state of the hardware, we decrement its timer word, and if it becomes
-// zero, we pretend the driver acknowledged.
+// All applications and kernel clients have acknowledged our permission to drop
+// power. Here we notify them that we will lower the power and wait for acks. 
 //*********************************************************************************
 
-void IOService::ack_timer_ticked ( void )
+void IOService::OurChangeTellClientsPowerDown ( void )
 {
-    IOPMinformee * nextObject;
-
-    if ( ! initialized ) {
-        return;                                        // we're unloading
-    }
-
-    if (! acquire_lock() ) {
-        return;
-    }
-    
-    switch (priv->machine_state) {
-        case IOPMour_prechange_2:
-        case IOPMparent_down_5:
-        case IOPMparent_up_4:
-            if ( priv->driver_timer != 0 ) {                            // are we waiting for our driver to make its change?
-                priv->driver_timer -= 1;                                // yes, tick once
-                if ( priv->driver_timer == 0 ) {                        // it's tardy, we'll go on without it
-                    IOUnlock(priv->our_lock);
-                    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogCtrlDriverTardy,0,0);
-                    driver_acked();
-                }
-                else {                                                  // still waiting, set timer again
-                    start_ack_timer();
-                    IOUnlock(priv->our_lock);
-                }
-            }
-            else {
-                IOUnlock(priv->our_lock);
-            }
-            break;
+    fMachineState = kIOPM_OurChangeTellPriorityClientsPowerDown;
+    tellChangeDown1(fHeadNotePowerState);
+}
 
-        case IOPMour_prechange_1:
-        case IOPMour_prechange_4:
-        case IOPMparent_down_4:
-        case IOPMparent_down_6:
-        case IOPMparent_up_0:
-        case IOPMparent_up_6:
-            if (priv->head_note_pendingAcks != 0 ) {                    // are we waiting for interested parties to acknowledge?
-                nextObject =  priv->interestedDrivers->firstInList();   // yes, go through the list of interested drivers
-                while (  nextObject != NULL ) {                         // and check each one
-                    if ( nextObject->timer > 0 ) {
-                        nextObject->timer -= 1;
-                        if ( nextObject->timer == 0 ) {                 // this one should have acked by now
-                            pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogIntDriverTardy,0,0);
-                            kprintf("interested driver tardy: %s\n",nextObject->whatObject->getName());
-                            priv->head_note_pendingAcks -= 1;
-                        }
-                    }
-                    nextObject  =  priv->interestedDrivers->nextInList(nextObject);
-                }
-                if ( priv->head_note_pendingAcks == 0 ) {       // is that the last?
-                    IOUnlock(priv->our_lock);
-                    all_acked();                                // yes, we can continue
-                }
-                else {                                          // no, set timer again
-                    start_ack_timer();
-                    IOUnlock(priv->our_lock);
-                }
-            }
-            else {
-                IOUnlock(priv->our_lock);
-            }
-            break;
+//*********************************************************************************
+// [private] OurChangeTellPriorityClientsPowerDown
+//
+// All applications and kernel clients have acknowledged our intention to drop
+// power.  Here we notify "priority" clients that we are lowering power.
+//*********************************************************************************
 
-        case IOPMparent_down_0:                                 // apps didn't respond to parent-down notification
-            IOUnlock(priv->our_lock);
-            IOLockLock(priv->flags_lock);
-            if (pm_vars->responseFlags) {
-                pm_vars->responseFlags->release();              // get rid of this stuff
-                pm_vars->responseFlags = NULL;
-            }
-            IOLockUnlock(priv->flags_lock);
-            pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogClientTardy,0,5);
-            parent_down_04();                                   // carry on with the change
-            break;
-            
-        case IOPMparent_down_05:
-            IOUnlock(priv->our_lock);
-            IOLockLock(priv->flags_lock);
-            if (pm_vars->responseFlags) {
-                pm_vars->responseFlags->release();              // get rid of this stuff
-                pm_vars->responseFlags = NULL;
-            }
-            IOLockUnlock(priv->flags_lock);
-            pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogClientTardy,0,1);
-            parent_down_05();                                   // carry on with the change
-            break;
-            
-        case IOPMour_prechange_03:                              // apps didn't respond to our power-down request
-            IOUnlock(priv->our_lock);
-            IOLockLock(priv->flags_lock);
-            if (pm_vars->responseFlags) {
-                pm_vars->responseFlags->release();              // get rid of this stuff
-                pm_vars->responseFlags = NULL;
-            }
-            IOLockUnlock(priv->flags_lock);
-            pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogClientTardy,0,2);
-            tellNoChangeDown(priv->head_note_state);           // rescind the request
-            priv->head_note_flags |= IOPMNotDone;              // mark the change note un-actioned
-            all_done();                                                // and we're done
-            break;
-            
-        case IOPMour_prechange_04:                              // clients didn't respond to our power-down note
-            IOUnlock(priv->our_lock);
-            IOLockLock(priv->flags_lock);
-            if (pm_vars->responseFlags) {
-                pm_vars->responseFlags->release();              // get rid of this stuff
-                pm_vars->responseFlags = NULL;
-            }
-            IOLockUnlock(priv->flags_lock);
-            pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogClientTardy,0,4);
-            our_prechange_04();                                // carry on with the change
-            break;
-            
-        case IOPMour_prechange_05:                              // apps didn't respond to our power-down notification
-            IOUnlock(priv->our_lock);
-            IOLockLock(priv->flags_lock);
-            if (pm_vars->responseFlags) {
-                pm_vars->responseFlags->release();              // get rid of this stuff
-                pm_vars->responseFlags = NULL;
-            }
-            IOLockUnlock(priv->flags_lock);
-            pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogClientTardy,0,3);
-            our_prechange_05();                                // carry on with the change
-            break;
-            
-        default:
-            IOUnlock(priv->our_lock);                           // not waiting for acks
-            break;
-    }
+void IOService::OurChangeTellPriorityClientsPowerDown ( void )
+{
+    fMachineState = kIOPM_OurChangeNotifyInterestedDriversWillChange;
+    tellChangeDown2(fHeadNotePowerState);
 }
 
-
 //*********************************************************************************
-// start_ack_timer
+// [private] OurChangeTellCapabilityWillChange
 //
+// Extra stage for root domain to notify apps and drivers about the
+// system capability change when raising power state.
 //*********************************************************************************
 
-void IOService::start_ack_timer ( void )
+void IOService::OurChangeTellCapabilityWillChange ( void )
 {
-    AbsoluteTime       deadline;
+    if (!IS_ROOT_DOMAIN)
+        return OurChangeNotifyInterestedDriversWillChange();
 
-    clock_interval_to_deadline(ACK_TIMER_PERIOD, kNanosecondScale, &deadline);
-    
-    thread_call_enter_delayed(priv->ackTimer, deadline);
+    tellSystemCapabilityChange( kIOPM_OurChangeNotifyInterestedDriversWillChange );
 }
 
-
 //*********************************************************************************
-// stop_ack_timer
+// [private] OurChangeNotifyInterestedDriversWillChange
 //
+// All applications and kernel clients have acknowledged our power state change.
+// Here we notify interested drivers pre-change.
 //*********************************************************************************
 
-void IOService::stop_ack_timer ( void )
+void IOService::OurChangeNotifyInterestedDriversWillChange ( void )
 {
-    thread_call_cancel(priv->ackTimer);
-}
+    IOPMrootDomain * rootDomain;
+    if ((rootDomain = getPMRootDomain()) == this)
+    {
+        if (IS_POWER_DROP)
+        {
+            rootDomain->tracePoint( kIOPMTracePointSleepWillChangeInterests );
+
+            PMEventDetails *details = PMEventDetails::eventDetails(
+                                        kIOPMEventTypeAppNotificationsFinished,
+                                        NULL,
+                                        100,
+                                        kIOReturnSuccess);
+            rootDomain->recordAndReleasePMEventGated( details );
+        }
+        else
+            rootDomain->tracePoint( kIOPMTracePointWakeWillChangeInterests );
+    }
 
+    notifyAll( kIOPM_OurChangeSetPowerState );
+}
 
 //*********************************************************************************
-// c-language timer expiration functions
+// [private] OurChangeSetPowerState
 //
+// Instruct our controlling driver to program the hardware for the power state
+// change. Wait for async completions.
 //*********************************************************************************
 
-static void ack_timer_expired ( thread_call_param_t us)
+void IOService::OurChangeSetPowerState ( void )
 {
-    ((IOService *)us)->ack_timer_ticked();
+    MS_PUSH( kIOPM_OurChangeWaitForPowerSettle );
+    fMachineState     = kIOPM_DriverThreadCallDone;
+    fDriverCallReason = kDriverCallSetPowerState;
+
+    if (notifyControllingDriver() == false)
+        notifyControllingDriverDone();
 }
 
+//*********************************************************************************
+// [private] OurChangeWaitForPowerSettle
+//
+// Our controlling driver has completed the power state change we initiated.
+// Wait for the driver specified settle time to expire.
+//*********************************************************************************
 
-static void settle_timer_expired ( thread_call_param_t us)
+void IOService::OurChangeWaitForPowerSettle ( void )
 {
-    ((IOService *)us)->settleTimerExpired();
+    fMachineState = kIOPM_OurChangeNotifyInterestedDriversDidChange;
+    startSettleTimer();
 }
 
-
 //*********************************************************************************
-// add_child_to_active_change
+// [private] OurChangeNotifyInterestedDriversDidChange
 //
-// A child has just registered with us.  If there is
-// currently a change in progress, get the new party involved: if we
-// have notified all parties and are waiting for acks, notify the new
-// party.
+// Power has settled on a power change we initiated. Here we notify
+// all our interested drivers post-change.
 //*********************************************************************************
 
-IOReturn IOService::add_child_to_active_change ( IOPowerConnection * newObject )
+void IOService::OurChangeNotifyInterestedDriversDidChange ( void )
 {
-    if (! acquire_lock() ) {
-        return IOPMNoErr;
+    IOPMrootDomain * rootDomain;
+    if ((rootDomain = getPMRootDomain()) == this)
+    {
+        rootDomain->tracePoint( IS_POWER_DROP ?
+            kIOPMTracePointSleepDidChangeInterests :
+            kIOPMTracePointWakeDidChangeInterests  );
     }
 
-    switch (priv->machine_state) {
-        case IOPMour_prechange_1:
-        case IOPMparent_down_4:
-        case IOPMparent_up_0:
-            priv->head_note_pendingAcks += 2;          // one for this child and one to prevent
-            IOUnlock(priv->our_lock);                  // incoming acks from changing our state
-            notifyChild(newObject, true);
-            if (! acquire_lock() ) {
-                --priv->head_note_pendingAcks;         // put it back
-                return IOPMNoErr;
-            }
-            if ( --priv->head_note_pendingAcks == 0 ) {        // are we still waiting for acks?
-                stop_ack_timer();                      // no, stop the timer
-                IOUnlock(priv->our_lock);
-                all_acked();                           // and now we can continue
-                return IOPMNoErr;
-            }
-            break;
-        case IOPMour_prechange_4:
-        case IOPMparent_down_6:
-        case IOPMparent_up_6:
-            priv->head_note_pendingAcks += 2;          // one for this child and one to prevent
-            IOUnlock(priv->our_lock);                  // incoming acks from changing our state
-            notifyChild(newObject, false);
-            if (! acquire_lock() ) {
-                --priv->head_note_pendingAcks;         // put it back
-                return IOPMNoErr;
-            }
-            if ( --priv->head_note_pendingAcks == 0 ) {        // are we still waiting for acks?
-                stop_ack_timer();                      // no, stop the timer
-                IOUnlock(priv->our_lock);
-                all_acked();                           // and now we can continue
-                return IOPMNoErr;
-            }
-            break;
-    }
-    IOUnlock(priv->our_lock);
-    return IOPMNoErr;
+    notifyAll( kIOPM_OurChangeTellCapabilityDidChange );
 }
 
-
 //*********************************************************************************
-// add_driver_to_active_change
+// [private] OurChangeTellCapabilityDidChange
 //
-// An interested driver has just registered with us.  If there is
-// currently a change in progress, get the new party involved: if we
-// have notified all parties and are waiting for acks, notify the new
-// party.
+// For root domain to notify capability power-change.
 //*********************************************************************************
 
-IOReturn IOService::add_driver_to_active_change ( IOPMinformee * newObject )
+void IOService::OurChangeTellCapabilityDidChange ( void )
 {
-    if (! acquire_lock() ) {
-        return IOPMNoErr;
-    }
+    if (!IS_ROOT_DOMAIN)
+        return OurChangeFinish();
 
-    switch (priv->machine_state) {
-        case IOPMour_prechange_1:
-        case IOPMparent_down_4:
-        case IOPMparent_up_0:
-            priv->head_note_pendingAcks += 2;          // one for this driver and one to prevent
-            IOUnlock(priv->our_lock);                  // incoming acks from changing our state
-            inform(newObject, true);                   // inform the driver
-            if (! acquire_lock() ) {
-                --priv->head_note_pendingAcks;         // put it back
-                return IOPMNoErr;
-            }
-            if ( --priv->head_note_pendingAcks == 0 ) {        // are we still waiting for acks?
-                stop_ack_timer();                      // no, stop the timer
-                IOUnlock(priv->our_lock);
-                all_acked();                           // and now we can continue
-                return IOPMNoErr;
-            }
-            break;
-        case IOPMour_prechange_4:
-        case IOPMparent_down_6:
-        case IOPMparent_up_6:
-            priv->head_note_pendingAcks += 2;          // one for this driver and one to prevent
-            IOUnlock(priv->our_lock);                  // incoming acks from changing our state
-            inform(newObject, false);                  // inform the driver
-            if (! acquire_lock() ) {
-                --priv->head_note_pendingAcks;         // put it back
-                return IOPMNoErr;
-            }
-            if ( --priv->head_note_pendingAcks == 0 ) {        // are we still waiting for acks?
-                stop_ack_timer();                      // no, stop the timer
-                IOUnlock(priv->our_lock);
-                all_acked();                           // and now we can continue
-                return IOPMNoErr;
-            }
-            break;
-    }
-    IOUnlock(priv->our_lock);
-    return IOPMNoErr;
-}
+    getPMRootDomain()->tracePoint( IS_POWER_DROP ?
+        kIOPMTracePointSleepCapabilityClients :
+        kIOPMTracePointWakeCapabilityClients  );
 
+    tellSystemCapabilityChange( kIOPM_OurChangeFinish );
+}
 
 //*********************************************************************************
-// start_parent_change
-//
-// Here we begin the processing of a change note  initiated by our parent
-// which is at the head of the queue.
+// [private] OurChangeFinish
 //
-// It is possible for the change to be processed to completion and removed from the queue.
-// There are several possible interruptions to the processing, though, and they are:
-// we may have to wait for interested parties to acknowledge our pre-change notification,
-// we may have to wait for our controlling driver to change the hardware power state,
-// there may be a settling time after changing the hardware power state,
-// we may have to wait for interested parties to acknowledge our post-change notification,
-// we may have to wait for the acknowledgement timer expiration to substitute for the
-// acknowledgement from a failing driver.
-//*********************************************************************************
-
-IOReturn IOService::start_parent_change ( unsigned long queue_head )
-{
-    priv->head_note = queue_head;
-    priv->head_note_flags = priv-> changeList->changeNote[priv->head_note].flags;
-    priv->head_note_state =  priv->changeList->changeNote[priv->head_note].newStateNumber;
-    priv->imminentState = priv->head_note_state;
-    priv->head_note_outputFlags =  priv->changeList->changeNote[priv->head_note].outputPowerCharacter;
-    priv->head_note_domainState = priv->changeList->changeNote[priv->head_note].domainState;
-    priv->head_note_parent = priv->changeList->changeNote[priv->head_note].parent;
-    priv->head_note_capabilityFlags =  priv->changeList->changeNote[priv->head_note].capabilityFlags;
-
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogStartParentChange,
-                    (unsigned long)priv->head_note_state,(unsigned long)pm_vars->myCurrentState);
-
-    ask_parent( priv->ourDesiredPowerState);                   // if we need something and haven't told the parent, do so
-
-    if ( priv->head_note_state < pm_vars->myCurrentState ) {    // power domain is lowering
-        setParentInfo(priv->changeList->changeNote[priv->head_note].singleParentState,priv->head_note_parent);
-       priv->initial_change = false;
-        priv->machine_state = IOPMparent_down_0;                // tell apps and kernel clients
-        if ( tellChangeDown1(priv->head_note_state) ) {        // are we waiting for responses?
-            return parent_down_0();                             // no, notify priority clients
-        }
-       return IOPMWillAckLater;                                 // yes
-    }
-
-    if ( priv->head_note_state > pm_vars->myCurrentState ) {           // parent is raising power, we may or may not
-        if ( priv->ourDesiredPowerState > pm_vars->myCurrentState ) {
-           if ( priv->ourDesiredPowerState < priv->head_note_state ) {
-               priv->head_note_state = priv->ourDesiredPowerState;     // we do, but not all the way
-               priv->imminentState = priv->head_note_state;
-               priv->head_note_outputFlags =   pm_vars->thePowerStates[priv->head_note_state].outputPowerCharacter;
-               priv->head_note_capabilityFlags =   pm_vars->thePowerStates[priv->head_note_state].capabilityFlags;
-               pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogAmendParentChange,(unsigned long)priv->head_note_state,0);
-            }
-        }
-        else {
-            priv->head_note_state = pm_vars->myCurrentState;           // we don't
-            priv->imminentState = priv->head_note_state;
-            priv->head_note_outputFlags =   pm_vars->thePowerStates[priv->head_note_state].outputPowerCharacter;
-            priv->head_note_capabilityFlags =   pm_vars->thePowerStates[priv->head_note_state].capabilityFlags;
-            pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogAmendParentChange,(unsigned long)priv->head_note_state,0);
-        }
-    }
-
-    if ( (priv->head_note_state > pm_vars->myCurrentState) &&
-         (priv->head_note_flags & IOPMDomainDidChange) ) {             // changing up
-        priv->initial_change = false;
-       priv->machine_state = IOPMparent_up_0;
-       if (  notifyAll(true) == IOPMAckImplied ) {
-            return parent_up_1();
-       }
-       return IOPMWillAckLater;                                        // they didn't all ack
-    }
+// Done with this self-induced power state change.
+//*********************************************************************************
 
+void IOService::OurChangeFinish ( void )
+{
     all_done();
-    return IOPMAckImplied;                                             // a null change or power will go up
 }
 
+// MARK: -
+// MARK: Power Change Initiated by Parent
 
 //*********************************************************************************
-// start_our_change
+// [private] ParentChangeStart
 //
-// Here we begin the processing of a change note  initiated by us
-// which is at the head of the queue.
-//
-// It is possible for the change to be processed to completion and removed from the queue.
-// There are several possible interruptions to the processing, though, and they are:
-// we may have to wait for interested parties to acknowledge our pre-change notification,
-// changes initiated by the parent will wait in the middle for powerStateDidChange,
-// we may have to wait for our controlling driver to change the hardware power state,
-// there may be a settling time after changing the hardware power state,
-// we may have to wait for interested parties to acknowledge our post-change notification,
-// we may have to wait for the acknowledgement timer expiration to substitute for the
-// acknowledgement from a failing driver.
-//*********************************************************************************
-
-void IOService::start_our_change ( unsigned long queue_head )
-{
-    priv->head_note = queue_head;
-    priv->head_note_flags =  priv->changeList->changeNote[priv->head_note].flags;
-    priv->head_note_state =  priv->changeList->changeNote[priv->head_note].newStateNumber;
-    priv->imminentState = priv->head_note_state;
-    priv->head_note_outputFlags =  priv->changeList->changeNote[priv->head_note].outputPowerCharacter;
-    priv->head_note_capabilityFlags =  priv->changeList->changeNote[priv->head_note].capabilityFlags;
-
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogStartDeviceChange,
-                (unsigned long)priv->head_note_state,(unsigned long)pm_vars->myCurrentState);
-
-    if ( priv->head_note_capabilityFlags & IOPMNotAttainable ) {       // can our driver switch to the new state?
-        if ( !  priv->we_are_root ) {                                  // no, ask the parent to do it then
-            ask_parent(priv->head_note_state);
-        }
-        priv-> head_note_flags |= IOPMNotDone;                         // mark the change note un-actioned
-        all_done();                                                    // and we're done
-        return;
-    }
-                                                                        // is there enough power in the domain?
-    if ( (pm_vars->maxCapability < priv->head_note_state) && (!  priv->we_are_root) ) {
-        if ( !  priv->we_are_root ) {                                  // no, ask the parent to raise it
-            ask_parent(priv->head_note_state);
-        }
-        priv->head_note_flags |= IOPMNotDone;                          // no, mark the change note un-actioned
-        all_done();                                                    // and we're done
-        return;                                                                // till the parent raises power
-    }
+// Here we begin the processing of a power change initiated by our parent.
+//*********************************************************************************
 
-    if ( !  priv->initial_change ) {
-        if ( priv->head_note_state == pm_vars->myCurrentState ) {
-            all_done();                                                // we initiated a null change; forget it
-            return;
-        }
+IOReturn IOService::ParentChangeStart ( void )
+{
+       PM_ASSERT_IN_GATE();
+    OUR_PMLog( kPMLogStartParentChange, fHeadNotePowerState, fCurrentPowerState );
+
+    // Power domain is lowering power
+    if ( fHeadNotePowerState < fCurrentPowerState )
+    {
+               // TODO: redundant? See handlePowerDomainWillChangeTo()
+               setParentInfo( fHeadNoteParentFlags, fHeadNoteParentConnection, true );
+
+        PM_ACTION_2(actionPowerChangeStart, fHeadNotePowerState, &fHeadNoteChangeFlags);
+
+       // Tell apps and kernel clients
+       fInitialPowerChange = false;
+        fMachineState = kIOPM_ParentChangeTellPriorityClientsPowerDown;
+               tellChangeDown1(fHeadNotePowerState);
+        return IOPMWillAckLater;
     }
-    priv->initial_change = false;
 
-    if ( priv->head_note_state < pm_vars->myCurrentState ) {   // dropping power?
-        priv->machine_state = IOPMour_prechange_03;            // yes, in case we have to wait for acks
-        pm_vars->doNotPowerDown = false;
-        if ( askChangeDown(priv->head_note_state) ) {                  // ask apps and kernel clients if we can drop power
-            if ( pm_vars->doNotPowerDown ) {                   // don't have to wait, did any clients veto?
-                tellNoChangeDown(priv->head_note_state);       // yes, rescind the warning
-                priv-> head_note_flags |= IOPMNotDone;         // mark the change note un-actioned
-                all_done();                                    // and we're done
-            }
-            else {
-                our_prechange_03();                            // no, tell'em we're dropping power
-            }
+    // Power domain is raising power
+    if ( fHeadNotePowerState > fCurrentPowerState )
+    {
+        if ( fDesiredPowerState > fCurrentPowerState )
+        {
+            if ( fDesiredPowerState < fHeadNotePowerState )
+            {
+                // We power up, but not all the way
+                fHeadNotePowerState = fDesiredPowerState;
+                               fHeadNotePowerArrayEntry = &fPowerStates[fDesiredPowerState];
+                OUR_PMLog(kPMLogAmendParentChange, fHeadNotePowerState, 0);
+             }
+        } else {
+            // We don't need to change
+            fHeadNotePowerState = fCurrentPowerState;
+                       fHeadNotePowerArrayEntry = &fPowerStates[fCurrentPowerState];                   
+            OUR_PMLog(kPMLogAmendParentChange, fHeadNotePowerState, 0);
         }
     }
-    else {
-        if ( !  priv->we_are_root ) {                          // we are raising power
-            ask_parent(priv->head_note_state);                 // if this changes our power requirement, tell the parent
+
+    if ( fHeadNoteChangeFlags & kIOPMDomainDidChange )
+       {
+        if ( fHeadNotePowerState > fCurrentPowerState )
+        {
+            PM_ACTION_2(actionPowerChangeStart,
+                fHeadNotePowerState, &fHeadNoteChangeFlags);
+
+            // Parent did change up - start our change up
+            fInitialPowerChange = false;            
+            ParentChangeTellCapabilityWillChange();
+            return IOPMWillAckLater;
         }
-        priv->machine_state = IOPMour_prechange_1;             // in case they don't all ack
-        if ( notifyAll(true) == IOPMAckImplied ) {             // notify interested drivers and children
-            our_prechange_1();
+        else if (fHeadNoteChangeFlags & kIOPMSynchronize)
+        {
+            // We do not need to change power state, but notify
+            // children to propagate tree synchronization.
+            fMachineState     = kIOPM_SyncNotifyDidChange;
+            fDriverCallReason = kDriverCallInformPreChange;
+            notifyChildren();
+            return IOPMWillAckLater;
         }
     }
+
+    all_done();
+    return IOPMAckImplied;
 }
 
+//*********************************************************************************
+// [private] ParentChangeTellPriorityClientsPowerDown
+//
+// All applications and kernel clients have acknowledged our intention to drop
+// power.  Here we notify "priority" clients that we are lowering power.
+//*********************************************************************************
+
+void IOService::ParentChangeTellPriorityClientsPowerDown ( void )
+{
+    fMachineState = kIOPM_ParentChangeNotifyInterestedDriversWillChange;
+       tellChangeDown2(fHeadNotePowerState);
+}
 
 //*********************************************************************************
-// ask_parent
+// [private] ParentChangeTellCapabilityWillChange
 //
-// Call the power domain parent to ask for a higher power state in the domain
-// or to suggest a lower power state.
+// All (legacy) applications and kernel clients have acknowledged, extra stage for
+// root domain to notify apps and drivers about the system capability change.
 //*********************************************************************************
 
-IOReturn IOService::ask_parent ( unsigned long requestedState )
+void IOService::ParentChangeTellCapabilityWillChange ( void )
 {
-    OSIterator *       iter;
-    OSObject *         next;
-    IOPowerConnection *        connection;
-    IOService *                parent;
-    unsigned long      ourRequest = pm_vars->thePowerStates[requestedState].inputPowerRequirement;
+    if (!IS_ROOT_DOMAIN)
+        return ParentChangeNotifyInterestedDriversWillChange();
 
-    if ( pm_vars->thePowerStates[requestedState].capabilityFlags & (kIOPMChildClamp | kIOPMPreventIdleSleep) ) {
-        ourRequest |= kIOPMPreventIdleSleep;
-    }
-    if ( pm_vars->thePowerStates[requestedState].capabilityFlags & (kIOPMChildClamp2 | kIOPMPreventSystemSleep) ) {
-        ourRequest |= kIOPMPreventSystemSleep;
-    }
-    
-    if ( priv->previousRequest == ourRequest ) {       // is this a new desire?
-        return IOPMNoErr;                              // no, the parent knows already, just return
-    }
+    tellSystemCapabilityChange( kIOPM_ParentChangeNotifyInterestedDriversWillChange );
+}
 
-    if (  priv->we_are_root ) {
-        return IOPMNoErr;
-    }
-    priv->previousRequest =  ourRequest;
+//*********************************************************************************
+// [private] ParentChangeNotifyInterestedDriversWillChange
+//
+// All applications and kernel clients have acknowledged our power state change.
+// Here we notify interested drivers pre-change.
+//*********************************************************************************
 
-    iter = getParentIterator(gIOPowerPlane);
+void IOService::ParentChangeNotifyInterestedDriversWillChange ( void )
+{
+       notifyAll( kIOPM_ParentChangeSetPowerState );
+}
 
-    if ( iter ) {
-        while ( (next = iter->getNextObject()) ) {
-            if ( (connection = OSDynamicCast(IOPowerConnection,next)) ) {
-                parent = (IOService *)connection->copyParentEntry(gIOPowerPlane);
-                if ( parent ) {
-                    if ( parent->requestPowerDomainState(ourRequest,connection,IOPMLowestState)!= IOPMNoErr ) {
-                        pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogRequestDenied,
-                                                                (unsigned long)priv->previousRequest,0);
-                    }
-                    parent->release();
-                }
-            }
-        }
-        iter->release();
+//*********************************************************************************
+// [private] ParentChangeSetPowerState
+//
+// Instruct our controlling driver to program the hardware for the power state
+// change. Wait for async completions.
+//*********************************************************************************
+
+void IOService::ParentChangeSetPowerState ( void )
+{
+    MS_PUSH( kIOPM_ParentChangeWaitForPowerSettle );
+    fMachineState     = kIOPM_DriverThreadCallDone;
+    fDriverCallReason = kDriverCallSetPowerState;
+
+    if (notifyControllingDriver() == false)
+        notifyControllingDriverDone();
+}
+
+//*********************************************************************************
+// [private] ParentChangeWaitForPowerSettle
+//
+// Our controlling driver has completed the power state change initiated by our
+// parent. Wait for the driver specified settle time to expire.
+//*********************************************************************************
+
+void IOService::ParentChangeWaitForPowerSettle ( void )
+{
+       fMachineState = kIOPM_ParentChangeNotifyInterestedDriversDidChange;
+    startSettleTimer();
+}
+
+//*********************************************************************************
+// [private] ParentChangeNotifyInterestedDriversDidChange
+//
+// Power has settled on a power change initiated by our parent. Here we notify
+// all our interested drivers post-change.
+//*********************************************************************************
+
+void IOService::ParentChangeNotifyInterestedDriversDidChange ( void )
+{
+       notifyAll( kIOPM_ParentChangeTellCapabilityDidChange ); 
+}
+
+//*********************************************************************************
+// [private] ParentChangeTellCapabilityDidChange
+//
+// For root domain to notify capability power-change.
+//*********************************************************************************
+
+void IOService::ParentChangeTellCapabilityDidChange ( void )
+{
+    if (!IS_ROOT_DOMAIN)
+        return ParentChangeAcknowledgePowerChange();
+
+    tellSystemCapabilityChange( kIOPM_ParentChangeAcknowledgePowerChange );
+}
+
+//*********************************************************************************
+// [private] ParentAcknowledgePowerChange
+//
+// Acknowledge our power parent that our power change is done. 
+//*********************************************************************************
+
+void IOService::ParentChangeAcknowledgePowerChange ( void )
+{
+    IORegistryEntry *  nub;
+    IOService *                        parent;
+
+    nub = fHeadNoteParentConnection;
+    nub->retain();
+    all_done();
+    parent = (IOService *)nub->copyParentEntry(gIOPowerPlane);
+    if ( parent )
+    {
+        parent->acknowledgePowerChange((IOService *)nub);
+        parent->release();
     }
+    nub->release();
+}
 
-    return IOPMNoErr;
+// MARK: -
+// MARK: Ack and Settle timers
+
+//*********************************************************************************
+// [private] settleTimerExpired
+//
+// Power has settled after our last change.  Notify interested parties that
+// there is a new power state.
+//*********************************************************************************
+
+void IOService::settleTimerExpired( void )
+{
+       fSettleTimeUS = 0;
+       gIOPMWorkQueue->signalWorkAvailable();
 }
 
+//*********************************************************************************
+// settle_timer_expired
+//
+// Holds a retain while the settle timer callout is in flight.
+//*********************************************************************************
+
+static void
+settle_timer_expired( thread_call_param_t arg0, thread_call_param_t arg1 )
+{
+       IOService * me = (IOService *) arg0;
+
+       if (gIOPMWorkLoop && gIOPMWorkQueue)
+       {
+               gIOPMWorkLoop->runAction(
+            OSMemberFunctionCast(IOWorkLoop::Action, me, &IOService::settleTimerExpired),
+            me);
+       }
+       me->release();
+}
 
 //*********************************************************************************
-// instruct_driver
+// [private] startSettleTimer
 //
-// Call the controlling driver and have it change the power state of the
-// hardware.  If it returns IOPMAckImplied, the change is complete, and
-// we return IOPMAckImplied.  Otherwise, it will ack when the change
-// is done; we return IOPMWillAckLater.
+// Calculate a power-settling delay in microseconds and start a timer.
 //*********************************************************************************
-IOReturn IOService::instruct_driver ( unsigned long newState )
+
+void IOService::startSettleTimer( void )
 {
-    IOReturn return_code;
+    AbsoluteTime        deadline;
+    IOPMPowerStateIndex i;
+    uint32_t            settleTime = 0;
+       boolean_t           pending;
 
-    if (  pm_vars->thePowerStates[newState].capabilityFlags & IOPMNotAttainable ) {    // can our driver switch to the desired state?
-        return IOPMAckImplied;                                         // no, so don't try
+       PM_ASSERT_IN_GATE();
+
+    i = fCurrentPowerState;
+
+    // lowering power
+    if ( fHeadNotePowerState < fCurrentPowerState )
+    {
+        while ( i > fHeadNotePowerState )
+        {
+            settleTime += (uint32_t) fPowerStates[i].settleDownTime;
+            i--;
+        }
     }
-    priv->driver_timer = -1;
-    
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogProgramHardware,newState,0);
 
-    return_code = pm_vars->theControllingDriver->setPowerState( newState,this );       // yes, instruct it
-    if ( return_code == IOPMAckImplied ) {                                     // it finished
-        priv->driver_timer = 0;
-        return IOPMAckImplied;
+    // raising power
+    if ( fHeadNotePowerState > fCurrentPowerState )
+    {
+        while ( i < fHeadNotePowerState )
+        {
+            settleTime += (uint32_t) fPowerStates[i+1].settleUpTime;
+            i++;
+        }
     }
 
-    if ( priv->driver_timer == 0 ) {                                           // it acked behind our back
-        return IOPMAckImplied;
+    if (settleTime)
+    {
+        retain();
+        clock_interval_to_deadline(settleTime, kMicrosecondScale, &deadline);
+        pending = thread_call_enter_delayed(fSettleTimer, deadline);
+        if (pending) release();
     }
+}
 
-    if ( return_code < 0 ) {                                                   // somebody goofed
-        return IOPMAckImplied;
+//*********************************************************************************
+// [private] ackTimerTick
+//
+// The acknowledgement timeout periodic timer has ticked.
+// If we are awaiting acks for a power change notification,
+// we decrement the timer word of each interested driver which hasn't acked.
+// If a timer word becomes zero, we pretend the driver aknowledged.
+// If we are waiting for the controlling driver to change the power
+// state of the hardware, we decrement its timer word, and if it becomes
+// zero, we pretend the driver acknowledged.
+//
+// Returns true if the timer tick made it possible to advance to the next
+// machine state, false otherwise.
+//*********************************************************************************
+
+#ifndef __LP64__
+void IOService::ack_timer_ticked ( void )
+{
+       assert(false);
+}
+#endif /* !__LP64__ */
+
+bool IOService::ackTimerTick( void )
+{
+    IOPMinformee *             nextObject;
+       bool                            done = false;
+
+       PM_ASSERT_IN_GATE();
+    switch (fMachineState) {
+        case kIOPM_OurChangeWaitForPowerSettle:
+        case kIOPM_ParentChangeWaitForPowerSettle:
+            // are we waiting for controlling driver to acknowledge?
+            if ( fDriverTimer > 0 )
+            {
+                // yes, decrement timer tick
+                fDriverTimer--;
+                if ( fDriverTimer == 0 )
+                {
+                    // controlling driver is tardy
+                    uint64_t nsec = computeTimeDeltaNS(&fDriverCallStartTime);
+                    OUR_PMLog(kPMLogCtrlDriverTardy, 0, 0);
+                    setProperty(kIOPMTardyAckSPSKey, kOSBooleanTrue);
+                    PM_ERROR("%s::setPowerState(%p, %lu -> %lu) timed out after %d ms\n",
+                        fName, this, fCurrentPowerState, fHeadNotePowerState, NS_TO_MS(nsec));
+
+#if LOG_SETPOWER_TIMES
+                    PMEventDetails *details = PMEventDetails::eventDetails(
+                                                kIOPMEventTypeSetPowerStateDelayed, // type
+                                                fName,                                                         // who
+                                                (uintptr_t)this,                                       // owner unique
+                                                NULL,                                                          // interest name
+                                                (uint8_t)getPowerState(),                      // old
+                                                0,                                                                     // new
+                                                kIOReturnTimeout,                                      // result
+                                                NS_TO_US(nsec));                                       // usec completion time
+                                       
+                    getPMRootDomain()->recordAndReleasePMEventGated( details );
+#endif
+
+                    if (gIOKitDebug & kIOLogDebugPower)
+                    {
+                        panic("%s::setPowerState(%p, %lu -> %lu) timed out after %d ms",
+                            fName, this, fCurrentPowerState, fHeadNotePowerState, NS_TO_MS(nsec));
+                    }
+                    else
+                                       {
+                                               // Unblock state machine and pretend driver has acked.
+                                               done = true;
+                                       }
+                } else {
+                    // still waiting, set timer again
+                    start_ack_timer();
+                }
+            }
+            break;
+
+        case kIOPM_NotifyChildrenStart:
+            // are we waiting for interested parties to acknowledge?
+            if ( fHeadNotePendingAcks != 0 )
+            {
+                // yes, go through the list of interested drivers
+                nextObject = fInterestedDrivers->firstInList();
+                // and check each one
+                while (  nextObject != NULL )
+                {
+                    if ( nextObject->timer > 0 )
+                    {
+                        nextObject->timer--;
+                        // this one should have acked by now
+                        if ( nextObject->timer == 0 )
+                        {
+                            uint64_t nsec = computeTimeDeltaNS(&nextObject->startTime);
+                            OUR_PMLog(kPMLogIntDriverTardy, 0, 0);
+                            nextObject->whatObject->setProperty(kIOPMTardyAckPSCKey, kOSBooleanTrue);
+                            PM_ERROR("%s::powerState%sChangeTo(%p, %s, %lu -> %lu) timed out after %d ms\n",
+                                nextObject->whatObject->getName(),
+                                (fDriverCallReason == kDriverCallInformPreChange) ? "Will" : "Did",
+                                nextObject->whatObject, fName, fCurrentPowerState, fHeadNotePowerState,
+                                NS_TO_MS(nsec));
+
+#if LOG_SETPOWER_TIMES
+                            uint16_t logType = (fDriverCallReason == kDriverCallInformPreChange) 
+                                                ? kIOPMEventTypePSWillChangeTo
+                                                : kIOPMEventTypePSDidChangeTo;
+                                                       
+                            PMEventDetails *details = PMEventDetails::eventDetails(
+                                                        logType,                                                         // type
+                                                        fName,                                                           // who
+                                                        (uintptr_t)this,                                         // owner unique
+                                                        nextObject->whatObject->getName(),       // interest name
+                                                        (uint8_t)fCurrentPowerState,             // old
+                                                        (uint8_t)fHeadNotePowerState,            // new
+                                                        kIOReturnTimeout,                                        // result
+                                                        NS_TO_US(nsec));                                         // usec completion time
+                                                       
+                            getPMRootDomain()->recordAndReleasePMEventGated( details );
+#endif
+
+                            // Pretend driver has acked.
+                            fHeadNotePendingAcks--;
+                        }
+                    }
+                    nextObject = fInterestedDrivers->nextInList(nextObject);
+                }
+
+                // is that the last?
+                if ( fHeadNotePendingAcks == 0 )
+                {
+                    // yes, we can continue
+                                       done = true;
+                } else {
+                    // no, set timer again
+                    start_ack_timer();
+                }
+            }
+            break;
+
+        // TODO: aggreggate this
+        case kIOPM_OurChangeTellClientsPowerDown:
+        case kIOPM_OurChangeTellPriorityClientsPowerDown:
+        case kIOPM_OurChangeNotifyInterestedDriversWillChange:
+        case kIOPM_ParentChangeTellPriorityClientsPowerDown:
+        case kIOPM_ParentChangeNotifyInterestedDriversWillChange:
+        case kIOPM_SyncTellClientsPowerDown:
+        case kIOPM_SyncTellPriorityClientsPowerDown:
+        case kIOPM_SyncNotifyWillChange:
+        case kIOPM_TellCapabilityChangeDone:
+                       // apps didn't respond in time
+            cleanClientResponses(true);
+            OUR_PMLog(kPMLogClientTardy, 0, 1);
+                       // tardy equates to approval
+                       done = true;
+            break;
+
+        default:
+            PM_LOG1("%s: unexpected ack timer tick (state = %d)\n",
+                               getName(), fMachineState);
+            break;
     }
-    priv->driver_timer = (return_code * ns_per_us / ACK_TIMER_PERIOD) + 1;     // it didn't finish
-    return IOPMWillAckLater;
+       return done;
+}
+
+//*********************************************************************************
+// [private] start_ack_timer
+//*********************************************************************************
+
+void IOService::start_ack_timer ( void )
+{
+       start_ack_timer( ACK_TIMER_PERIOD, kNanosecondScale );
+}
+
+void IOService::start_ack_timer ( UInt32 interval, UInt32 scale )
+{
+    AbsoluteTime       deadline;
+       boolean_t               pending;
+
+    clock_interval_to_deadline(interval, scale, &deadline);
+
+       retain();
+    pending = thread_call_enter_delayed(fAckTimer, deadline);
+       if (pending) release();
 }
 
+//*********************************************************************************
+// [private] stop_ack_timer
+//*********************************************************************************
+
+void IOService::stop_ack_timer ( void )
+{
+       boolean_t               pending;
+
+    pending = thread_call_cancel(fAckTimer);
+       if (pending) release();
+}
 
 //*********************************************************************************
-// acquire_lock
+// [static] actionAckTimerExpired
 //
-// We are acquiring the lock we use to protect our queue head from
-// simutaneous access by a thread which calls acknowledgePowerStateChange
-// or acknowledgeSetPowerState and the ack timer expiration thread.
-// Return TRUE if we acquire the lock, and the queue head didn't change
-// while we were acquiring the lock (and maybe blocked).
-// If there is no queue head, or it changes while we are blocked,
-// return FALSE with the lock unlocked.
+// Inside PM work loop's gate.
 //*********************************************************************************
 
-bool IOService::acquire_lock ( void )
+IOReturn
+IOService::actionAckTimerExpired (
+       OSObject * target,
+       void * arg0, void * arg1,
+       void * arg2, void * arg3 )
 {
-    long current_change_note;
+       IOService * me = (IOService *) target;
+       bool            done;
 
-    current_change_note = priv->head_note;
-    if ( current_change_note == -1 ) {
-        return FALSE;
-    }
+       // done will be true if the timer tick unblocks the machine state,
+       // otherwise no need to signal the work loop.
+
+       done = me->ackTimerTick();
+       if (done && gIOPMWorkQueue)
+               gIOPMWorkQueue->signalWorkAvailable();
+
+       return kIOReturnSuccess;
+}
+
+//*********************************************************************************
+// ack_timer_expired
+//
+// Thread call function. Holds a retain while the callout is in flight.
+//*********************************************************************************
+
+void
+IOService::ack_timer_expired ( thread_call_param_t arg0, thread_call_param_t arg1 )
+{
+       IOService * me = (IOService *) arg0;
+
+       if (gIOPMWorkLoop)
+       {
+               gIOPMWorkLoop->runAction(&actionAckTimerExpired, me);
+       }
+       me->release();
+}
+
+// MARK: -
+// MARK: Client Messaging
+
+//*********************************************************************************
+// [private] tellSystemCapabilityChange
+//*********************************************************************************
 
-    IOTakeLock(priv->our_lock);
-    if ( current_change_note == priv->head_note ) {
-        return TRUE;
+void IOService::tellSystemCapabilityChange( uint32_t nextMS )
+{
+       MS_PUSH( nextMS );
+    fMachineState       = kIOPM_TellCapabilityChangeDone;
+    fOutOfBandMessage   = kIOMessageSystemCapabilityChange;
+
+    if (fIsPreChange)
+    {
+        // Notify app first on pre-change.
+        fOutOfBandParameter = kNotifyCapabilityChangeApps;
     }
-    else {                                     // we blocked and something changed radically
-        IOUnlock(priv->our_lock);              // so there's nothing to do any more
-        return FALSE;
+    else
+    {
+        // Notify kernel clients first on post-change.
+        fOutOfBandParameter = kNotifyCapabilityChangePriority;
     }
-}
 
+    tellClientsWithResponse( fOutOfBandMessage );
+}
 
 //*********************************************************************************
-// askChangeDown
+// [public] askChangeDown
 //
 // Ask registered applications and kernel clients if we can change to a lower
 // power state.
@@ -3321,12 +5001,11 @@ bool IOService::acquire_lock ( void )
 
 bool IOService::askChangeDown ( unsigned long stateNum )
 {
-    return tellClientsWithResponse(kIOMessageCanDevicePowerOff);
+    return tellClientsWithResponse( kIOMessageCanDevicePowerOff );
 }
 
-
 //*********************************************************************************
-// tellChangeDown1
+// [private] tellChangeDown1
 //
 // Notify registered applications and kernel clients that we are definitely
 // dropping power.
@@ -3336,13 +5015,12 @@ bool IOService::askChangeDown ( unsigned long stateNum )
 
 bool IOService::tellChangeDown1 ( unsigned long stateNum )
 {
-    pm_vars->outofbandparameter = kNotifyApps;
+    fOutOfBandParameter = kNotifyApps;
     return tellChangeDown(stateNum);
 }
 
-
 //*********************************************************************************
-// tellChangeDown2
+// [private] tellChangeDown2
 //
 // Notify priority clients that we are definitely dropping power.
 //
@@ -3351,13 +5029,12 @@ bool IOService::tellChangeDown1 ( unsigned long stateNum )
 
 bool IOService::tellChangeDown2 ( unsigned long stateNum )
 {
-    pm_vars->outofbandparameter = kNotifyPriority;
+    fOutOfBandParameter = kNotifyPriority;
     return tellChangeDown(stateNum);
 }
 
-
 //*********************************************************************************
-// tellChangeDown
+// [public] tellChangeDown
 //
 // Notify registered applications and kernel clients that we are definitely
 // dropping power.
@@ -3370,12 +5047,103 @@ bool IOService::tellChangeDown2 ( unsigned long stateNum )
 
 bool IOService::tellChangeDown ( unsigned long stateNum )
 {
-    return tellClientsWithResponse(kIOMessageDeviceWillPowerOff);
+    return tellClientsWithResponse( kIOMessageDeviceWillPowerOff );
+}
+
+//*********************************************************************************
+// cleanClientResponses
+//
+//*********************************************************************************
+
+static void logAppTimeouts ( OSObject * object, void * arg )
+{
+    IOPMInterestContext *   context = (IOPMInterestContext *) arg;
+    OSObject *              flag;
+    unsigned int            clientIndex;
+
+    if (OSDynamicCast(_IOServiceInterestNotifier, object))
+    {
+        // Discover the 'counter' value or index assigned to this client
+        // when it was notified, by searching for the array index of the
+        // client in an array holding the cached interested clients.
+
+        clientIndex = context->notifyClients->getNextIndexOfObject(object, 0);
+
+        if ((clientIndex != (unsigned int) -1) &&
+            (flag = context->responseArray->getObject(clientIndex)) &&
+            (flag != kOSBooleanTrue))
+        {
+            OSString * clientID = 0;
+            context->us->messageClient(context->messageType, object, &clientID);
+            PM_ERROR(context->errorLog, clientID ? clientID->getCStringNoCopy() : "");
+
+            // TODO: record message type if possible
+            IOService::getPMRootDomain()->pmStatsRecordApplicationResponse(
+                gIOPMStatsApplicationResponseTimedOut,
+                clientID ? clientID->getCStringNoCopy() : "",
+                0, (30*1000), -1);
+
+            if (clientID)
+                clientID->release();
+        }
+    }
 }
 
+void IOService::cleanClientResponses ( bool logErrors )
+{
+    if (logErrors && fResponseArray)
+    {
+        switch ( fOutOfBandParameter ) {
+            case kNotifyApps:
+            case kNotifyCapabilityChangeApps:
+                if (fNotifyClientArray)
+                {
+                    IOPMInterestContext context;
+
+                    context.responseArray    = fResponseArray;
+                    context.notifyClients    = fNotifyClientArray;
+                    context.serialNumber     = fSerialNumber;
+                    context.messageType      = kIOMessageCopyClientID;
+                    context.notifyType       = kNotifyApps;
+                    context.isPreChange      = fIsPreChange;
+                    context.enableTracing    = false;
+                    context.us               = this;
+                    context.maxTimeRequested = 0;
+                    context.stateNumber      = fHeadNotePowerState;
+                    context.stateFlags       = fHeadNotePowerArrayEntry->capabilityFlags;
+                    context.changeFlags      = fHeadNoteChangeFlags;
+                    context.errorLog         = "PM notification timeout (%s)\n";
+
+                    applyToInterested(gIOAppPowerStateInterest, logAppTimeouts, (void *) &context);
+                }
+                break;
+
+            default:
+                // kNotifyPriority, kNotifyCapabilityChangePriority
+                // TODO: identify the priority client that has not acked
+                PM_ERROR("PM priority notification timeout\n");
+                if (gIOKitDebug & kIOLogDebugPower)
+                {
+                    panic("PM priority notification timeout");
+                }
+                break;
+        }
+    }
+
+    if (fResponseArray)
+    {
+        fResponseArray->release();
+        fResponseArray = NULL;
+    }
+    if (fNotifyClientArray)
+    {
+        fNotifyClientArray->release();
+        fNotifyClientArray = NULL;
+    }
+}
 
 //*********************************************************************************
-// tellClientsWithResponse
+// [protected] tellClientsWithResponse
 //
 // Notify registered applications and kernel clients that we are definitely
 // dropping power.
@@ -3385,168 +5153,490 @@ bool IOService::tellChangeDown ( unsigned long stateNum )
 
 bool IOService::tellClientsWithResponse ( int messageType )
 {
-    struct context      theContext;
-    AbsoluteTime        deadline;
-    OSBoolean *         aBool;
-
-    pm_vars->responseFlags = OSArray::withCapacity( 1 );
-    pm_vars->serialNumber += 1;
-    
-    theContext.responseFlags = pm_vars->responseFlags;
-    theContext.serialNumber = pm_vars->serialNumber;
-    theContext.flags_lock = priv->flags_lock;
-    theContext.counter = 1;
-    theContext.msgType = messageType;
-    theContext.us = this;
-    theContext.maxTimeRequested = 0;
-    theContext.stateNumber = priv->head_note_state;
-    theContext.stateFlags = priv->head_note_capabilityFlags;
-
-    IOLockLock(priv->flags_lock);
-    aBool = OSBoolean::withBoolean(false);             // position zero is false to   
-    theContext.responseFlags->setObject(0,aBool);      // prevent allowCancelCommon from succeeding
-    aBool->release();
-    IOLockUnlock(priv->flags_lock);
-
-    switch ( pm_vars->outofbandparameter ) {
+    IOPMInterestContext     context;
+    bool                    isRootDomain = IS_ROOT_DOMAIN;
+
+       PM_ASSERT_IN_GATE();
+    assert( fResponseArray == NULL );
+    assert( fNotifyClientArray == NULL );
+
+    RD_LOG("tellClientsWithResponse( %s, %d )\n",
+        getIOMessageString(messageType), fOutOfBandParameter);
+
+    fResponseArray = OSArray::withCapacity( 1 );
+    if (!fResponseArray)
+        goto exit;
+
+    fResponseArray->setCapacityIncrement(8);
+    if (++fSerialNumber == 0)
+        fSerialNumber++;        
+
+    context.responseArray    = fResponseArray;
+    context.notifyClients    = 0;
+    context.serialNumber     = fSerialNumber;
+    context.messageType      = messageType;
+    context.notifyType       = fOutOfBandParameter;
+    context.isPreChange      = fIsPreChange;
+    context.enableTracing    = false;
+    context.us               = this;
+    context.maxTimeRequested = 0;
+    context.stateNumber      = fHeadNotePowerState;
+    context.stateFlags       = fHeadNotePowerArrayEntry->capabilityFlags;
+    context.changeFlags      = fHeadNoteChangeFlags;
+    context.messageFilter    = (isRootDomain) ?
+                               OSMemberFunctionCast(
+                                    IOPMMessageFilter,
+                                    this,
+                                    &IOPMrootDomain::systemMessageFilter) : 0;
+
+    switch ( fOutOfBandParameter ) {
         case kNotifyApps:
-            applyToInterested(gIOAppPowerStateInterest,tellAppWithResponse,(void *)&theContext);
-            applyToInterested(gIOGeneralInterest,tellClientWithResponse,(void *)&theContext);
+            applyToInterested( gIOAppPowerStateInterest,
+                               pmTellAppWithResponse, (void *) &context );
+
+            if (isRootDomain &&
+                (fMachineState != kIOPM_OurChangeTellClientsPowerDown) &&
+                (fMachineState != kIOPM_SyncTellClientsPowerDown))
+            {
+                // Notify capability app for tellChangeDown1()
+                // but not for askChangeDown().
+                context.notifyType  = kNotifyCapabilityChangeApps;
+                context.messageType = kIOMessageSystemCapabilityChange;
+                applyToInterested( gIOAppPowerStateInterest,
+                    pmTellCapabilityAppWithResponse, (void *) &context ); 
+                context.notifyType  = fOutOfBandParameter;
+                context.messageType = messageType;
+            }
+            context.maxTimeRequested = k30seconds;
+
+            applyToInterested( gIOGeneralInterest,
+                               pmTellClientWithResponse, (void *) &context );
+
+            fNotifyClientArray = context.notifyClients;
             break;
+
         case kNotifyPriority:
-            applyToInterested(gIOPriorityPowerStateInterest,tellClientWithResponse,(void *)&theContext);
+            context.enableTracing = isRootDomain;
+            applyToInterested( gIOPriorityPowerStateInterest,
+                               pmTellClientWithResponse, (void *) &context );
+
+            if (isRootDomain)
+            {
+                // Notify capability clients for tellChangeDown2().
+                context.notifyType  = kNotifyCapabilityChangePriority;
+                context.messageType = kIOMessageSystemCapabilityChange;
+                applyToInterested( gIOPriorityPowerStateInterest,
+                    pmTellCapabilityClientWithResponse, (void *) &context );
+            }
             break;
-    }
 
-    if (! acquire_lock() ) {
-        return true;
+        case kNotifyCapabilityChangeApps:
+            applyToInterested( gIOAppPowerStateInterest,
+                               pmTellCapabilityAppWithResponse, (void *) &context );
+            fNotifyClientArray = context.notifyClients;
+            context.maxTimeRequested = k30seconds;
+            break;
+
+        case kNotifyCapabilityChangePriority:
+            applyToInterested( gIOPriorityPowerStateInterest,
+                               pmTellCapabilityClientWithResponse, (void *) &context );
+            break;
     }
-    IOLockLock(priv->flags_lock);
-    aBool = OSBoolean::withBoolean(true);              // now fix position zero
-    theContext.responseFlags->replaceObject(0,aBool);
-    aBool->release();
-    IOLockUnlock(priv->flags_lock);
-    
-    if ( ! checkForDone() ) {                          // we have to wait for somebody
-        pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogStartAckTimer,theContext.maxTimeRequested,0);
-        clock_interval_to_deadline(theContext.maxTimeRequested / 1000, kMillisecondScale, &deadline);
-        
-        thread_call_enter_delayed(priv->ackTimer, deadline);
-    
-        IOUnlock(priv->our_lock);                      // yes
+
+    // do we have to wait for somebody?
+    if ( !checkForDone() )
+    {
+        OUR_PMLog(kPMLogStartAckTimer, context.maxTimeRequested, 0);
+        if (context.enableTracing)
+            getPMRootDomain()->traceDetail( context.maxTimeRequested / 1000 );
+               start_ack_timer( context.maxTimeRequested / 1000, kMillisecondScale );  
         return false;
     }
-    
-    IOUnlock(priv->our_lock);
-    IOLockLock(priv->flags_lock);
-    pm_vars->responseFlags->release();                 // everybody responded    
-    pm_vars->responseFlags = NULL;
-    IOLockUnlock(priv->flags_lock);
-    
+
+exit:
+    // everybody responded
+    if (fResponseArray)
+    {
+        fResponseArray->release();
+        fResponseArray = NULL;
+    }
+    if (fNotifyClientArray)
+    {
+        fNotifyClientArray->release();
+        fNotifyClientArray = NULL;
+    }
+
     return true;
 }
 
-
 //*********************************************************************************
-// tellAppWithResponse
+// [static private] pmTellAppWithResponse
 //
 // We send a message to an application, and we expect a response, so we compute a
 // cookie we can identify the response with.
 //*********************************************************************************
-void tellAppWithResponse ( OSObject * object, void * context)
+
+void IOService::pmTellAppWithResponse ( OSObject * object, void * arg )
 {
-    struct context *    theContext = (struct context *)context;
-    UInt32              refcon;
-    OSBoolean *         aBool;
-    
-    if( OSDynamicCast( IOService, object) ) {
-        IOLockLock(theContext->flags_lock);
-        aBool = OSBoolean::withBoolean(true);
-        theContext->responseFlags->setObject(theContext->counter,aBool);
-        aBool->release();
-        IOLockUnlock(theContext->flags_lock);
-    }
-    else {
-        refcon = ((theContext->serialNumber & 0xFFFF)<<16) + (theContext->counter & 0xFFFF);
-        IOLockLock(theContext->flags_lock);
-        aBool = OSBoolean::withBoolean(false);
-        theContext->responseFlags->setObject(theContext->counter,aBool);
-        aBool->release();
-        IOLockUnlock(theContext->flags_lock);
-        theContext->us->messageClient(theContext->msgType,object,(void *)refcon);
-        if ( theContext->maxTimeRequested < k30seconds ) {
-            theContext->maxTimeRequested = k30seconds;
+    IOPMInterestContext *   context = (IOPMInterestContext *) arg;
+    IOServicePM *           pwrMgt = context->us->pwrMgt;
+    uint32_t                msgIndex, msgRef, msgType;
+#if LOG_APP_RESPONSE_TIMES
+    AbsoluteTime            now;
+#endif
+
+    if (!OSDynamicCast(_IOServiceInterestNotifier, object))
+        return;
+
+    if (context->messageFilter &&
+        !context->messageFilter(context->us, object, context, 0, 0))
+    {
+        if (kIOLogDebugPower & gIOKitDebug)
+        {
+            // Log client pid/name and client array index.
+            OSString * clientID = 0;
+            context->us->messageClient(kIOMessageCopyClientID, object, &clientID);
+            PM_LOG("%s DROP App %s, %s\n",
+                context->us->getName(),
+                getIOMessageString(context->messageType),
+                clientID ? clientID->getCStringNoCopy() : "");
+            if (clientID) clientID->release();
         }
+        return;
     }
-    theContext->counter += 1;
-}
 
+    // Create client array (for tracking purposes) only if the service
+    // has app clients. Usually only root domain does.
+    if (0 == context->notifyClients)
+        context->notifyClients = OSArray::withCapacity( 32 );
+
+    msgType  = context->messageType;
+    msgIndex = context->responseArray->getCount();
+    msgRef   = ((context->serialNumber & 0xFFFF) << 16) + (msgIndex & 0xFFFF);
+
+    OUR_PMLog(kPMLogAppNotify, msgType, msgRef);
+    if (kIOLogDebugPower & gIOKitDebug)
+    {
+        // Log client pid/name and client array index.
+        OSString * clientID = 0;
+        context->us->messageClient(kIOMessageCopyClientID, object, &clientID);
+        PM_LOG("%s MESG App(%u) %s, %s\n",
+            context->us->getName(),
+            msgIndex, getIOMessageString(msgType),
+            clientID ? clientID->getCStringNoCopy() : "");
+        if (clientID) clientID->release();
+    }
+
+#if LOG_APP_RESPONSE_TIMES
+    OSNumber * num;
+    clock_get_uptime(&now);
+    num = OSNumber::withNumber(AbsoluteTime_to_scalar(&now), sizeof(uint64_t) * 8);
+    if (num)
+    {
+        context->responseArray->setObject(msgIndex, num);
+        num->release();
+    }
+    else
+#endif
+    context->responseArray->setObject(msgIndex, kOSBooleanFalse);
+
+    if (context->notifyClients)
+        context->notifyClients->setObject(msgIndex, object);
+
+    context->us->messageClient(msgType, object, (void *) msgRef);
+}
 
 //*********************************************************************************
-// tellClientWithResponse
+// [static private] pmTellClientWithResponse
 //
-// We send a message to an in-kernel client, and we expect a response, so we compute a
-// cookie we can identify the response with.
-// If it doesn't understand the notification (it is not power-management savvy)
-// we won't wait for it to prepare for sleep.  If it tells us via a return code
-// in the passed struct that it is currently ready, we won't wait for it to prepare.
-// If it tells us via the return code in the struct that it does need time, we will chill.
+// We send a message to an in-kernel client, and we expect a response,
+// so we compute a cookie we can identify the response with.
 //*********************************************************************************
-void tellClientWithResponse ( OSObject * object, void * context)
+
+void IOService::pmTellClientWithResponse ( OSObject * object, void * arg )
 {
-    struct context *                   theContext = (struct context *)context;
-    IOPowerStateChangeNotification     notify;
-    UInt32                             refcon;
-    IOReturn                           retCode;
-    OSBoolean *                        aBool;
-    OSObject *                         theFlag;
-    
-    refcon = ((theContext->serialNumber & 0xFFFF)<<16) + (theContext->counter & 0xFFFF);
-    IOLockLock(theContext->flags_lock);
-    aBool = OSBoolean::withBoolean(false);
-    theContext->responseFlags->setObject(theContext->counter,aBool);
-    aBool->release();
-    IOLockUnlock(theContext->flags_lock);
-
-    notify.powerRef = (void *)refcon;
-    notify.returnValue = 0;
-    notify.stateNumber = theContext->stateNumber;
-    notify.stateFlags = theContext->stateFlags;
-    retCode = theContext->us->messageClient(theContext->msgType,object,(void *)&notify);
-    if ( retCode == kIOReturnSuccess ) {
-        if ( notify.returnValue == 0 ) {                                               // client doesn't want time to respond
-            IOLockLock(theContext->flags_lock);
-            aBool = OSBoolean::withBoolean(true);
-            theContext->responseFlags->replaceObject(theContext->counter,aBool);       // so set its flag true
-            aBool->release();
-            IOLockUnlock(theContext->flags_lock);
+    IOPowerStateChangeNotification  notify;
+    IOPMInterestContext *           context = (IOPMInterestContext *) arg;
+    OSObject *                      replied = kOSBooleanTrue;
+    _IOServiceInterestNotifier *    notifier;
+    uint32_t                        msgIndex, msgRef, msgType;
+    IOReturn                        retCode;
+
+    if (context->messageFilter &&
+        !context->messageFilter(context->us, object, context, 0, 0))
+    {
+        if ((kIOLogDebugPower & gIOKitDebug) &&
+            (OSDynamicCast(_IOServiceInterestNotifier, object)))
+        {
+            _IOServiceInterestNotifier *n = (_IOServiceInterestNotifier *) object;
+            PM_LOG("%s DROP Client %s, notifier %p, handler %p\n",
+                context->us->getName(),
+                getIOMessageString(context->messageType),
+                object, n->handler);
+               }        
+        return;
+    }
+
+    notifier = OSDynamicCast(_IOServiceInterestNotifier, object);
+    msgType  = context->messageType;
+    msgIndex = context->responseArray->getCount();
+    msgRef   = ((context->serialNumber & 0xFFFF) << 16) + (msgIndex & 0xFFFF);
+
+    IOServicePM * pwrMgt = context->us->pwrMgt;
+    if (gIOKitDebug & kIOLogPower) {
+               OUR_PMLog(kPMLogClientNotify, msgRef, msgType);
+               if (OSDynamicCast(IOService, object)) {
+                       const char *who = ((IOService *) object)->getName();
+                       gPlatform->PMLog(who, kPMLogClientNotify, (uintptr_t) object, 0);
+               }
+        else if (notifier) {
+                       OUR_PMLog(kPMLogClientNotify, (uintptr_t) notifier->handler, 0);
         }
-        else {
-            IOLockLock(theContext->flags_lock);
-            theFlag = theContext->responseFlags->getObject(theContext->counter);       // it does want time, and it hasn't
-            if ( theFlag != 0 ) {                                                      // responded yet
-                if ( ((OSBoolean *)theFlag)->isFalse() ) {                             // so note its time requirement
-                    if ( theContext->maxTimeRequested < notify.returnValue ) {
-                        theContext->maxTimeRequested = notify.returnValue;
-                    }
+    }
+    if ((kIOLogDebugPower & gIOKitDebug) && notifier)
+    {
+        PM_LOG("%s MESG Client %s, notifier %p, handler %p\n",
+            context->us->getName(),
+            getIOMessageString(msgType),
+            object, notifier->handler);
+    }
+
+    notify.powerRef    = (void *)(uintptr_t) msgRef;
+    notify.returnValue = 0;
+    notify.stateNumber = context->stateNumber;
+    notify.stateFlags  = context->stateFlags;
+
+    if (context->enableTracing && (notifier != 0))
+    {
+        uint32_t detail = ((msgIndex & 0xff) << 24) |
+                          ((msgType & 0xfff) << 12) |
+                          (((uintptr_t) notifier->handler) & 0xfff);
+        getPMRootDomain()->traceDetail( detail );
+    }
+
+    retCode = context->us->messageClient(msgType, object, (void *) &notify);
+    if ( kIOReturnSuccess == retCode )
+    {
+        if ( 0 == notify.returnValue )
+        {
+            // client doesn't want time to respond
+                       OUR_PMLog(kPMLogClientAcknowledge, msgRef, (uintptr_t) object);
+        }
+        else
+        {
+            replied = kOSBooleanFalse;
+            if ( notify.returnValue > context->maxTimeRequested )
+            {
+                if (notify.returnValue > kPriorityClientMaxWait)
+                {
+                    context->maxTimeRequested = kPriorityClientMaxWait;
+                    PM_ERROR("%s: client %p returned %llu for %s\n",
+                        context->us->getName(),
+                        notifier ? (void *)  notifier->handler : object,
+                        (uint64_t) notify.returnValue,
+                        getIOMessageString(msgType));
                 }
+                else
+                    context->maxTimeRequested = notify.returnValue;
             }
-            IOLockUnlock(theContext->flags_lock);
         }
     }
-    else {                                                                     // not a client of ours
-        IOLockLock(theContext->flags_lock);
-        aBool = OSBoolean::withBoolean(true);                                  // so we won't be waiting for response
-        theContext->responseFlags->replaceObject(theContext->counter,aBool);
-        aBool->release();
-        IOLockUnlock(theContext->flags_lock);
+    else
+    {
+        // not a client of ours
+        // so we won't be waiting for response
+               OUR_PMLog(kPMLogClientAcknowledge, msgRef, 0);
+    }
+
+    context->responseArray->setObject(msgIndex, replied);
+}
+
+//*********************************************************************************
+// [static private] pmTellCapabilityAppWithResponse
+//*********************************************************************************
+
+void IOService::pmTellCapabilityAppWithResponse ( OSObject * object, void * arg )
+{
+    IOPMSystemCapabilityChangeParameters msgArg;
+    IOPMInterestContext *       context = (IOPMInterestContext *) arg;
+    OSObject *                  replied = kOSBooleanTrue;
+    IOServicePM *               pwrMgt = context->us->pwrMgt;
+    uint32_t                    msgIndex, msgRef, msgType;
+#if LOG_APP_RESPONSE_TIMES
+    AbsoluteTime                now;
+#endif
+
+    if (!OSDynamicCast(_IOServiceInterestNotifier, object))
+        return;
+
+    memset(&msgArg, 0, sizeof(msgArg));
+    if (context->messageFilter &&
+        !context->messageFilter(context->us, object, context, &msgArg, &replied))
+    {
+        return;
+    }
+
+    // Create client array (for tracking purposes) only if the service
+    // has app clients. Usually only root domain does.
+    if (0 == context->notifyClients)
+        context->notifyClients = OSArray::withCapacity( 32 );
+
+    msgType  = context->messageType;
+    msgIndex = context->responseArray->getCount();
+    msgRef   = ((context->serialNumber & 0xFFFF) << 16) + (msgIndex & 0xFFFF);
+
+    OUR_PMLog(kPMLogAppNotify, msgType, msgRef);
+    if (kIOLogDebugPower & gIOKitDebug)
+    {
+        // Log client pid/name and client array index.
+        OSString * clientID = 0;
+        context->us->messageClient(kIOMessageCopyClientID, object, &clientID);
+        PM_LOG("%s MESG App(%u) %s, wait %u, %s\n",
+            context->us->getName(),
+            msgIndex, getIOMessageString(msgType),
+            (replied != kOSBooleanTrue),
+            clientID ? clientID->getCStringNoCopy() : "");
+        if (clientID) clientID->release();
+    }
+
+    msgArg.notifyRef = msgRef;
+    msgArg.maxWaitForReply = 0;
+
+    if (replied == kOSBooleanTrue)
+    {
+        msgArg.notifyRef = 0;
+        context->responseArray->setObject(msgIndex, kOSBooleanTrue);
+        if (context->notifyClients)
+            context->notifyClients->setObject(msgIndex, kOSBooleanTrue);
+    }
+    else
+    {
+#if LOG_APP_RESPONSE_TIMES
+        OSNumber * num;
+        clock_get_uptime(&now);
+        num = OSNumber::withNumber(AbsoluteTime_to_scalar(&now), sizeof(uint64_t) * 8);
+        if (num)
+        {
+            context->responseArray->setObject(msgIndex, num);
+            num->release();
+        }
+        else
+#endif
+        context->responseArray->setObject(msgIndex, kOSBooleanFalse);
+
+        if (context->notifyClients)
+            context->notifyClients->setObject(msgIndex, object);
     }
-    theContext->counter += 1;
+
+    context->us->messageClient(msgType, object, (void *) &msgArg, sizeof(msgArg));
 }
 
+//*********************************************************************************
+// [static private] pmTellCapabilityClientWithResponse
+//*********************************************************************************
+
+void IOService::pmTellCapabilityClientWithResponse(
+    OSObject * object, void * arg )
+{
+    IOPMSystemCapabilityChangeParameters msgArg;
+    IOPMInterestContext *           context = (IOPMInterestContext *) arg;
+    OSObject *                      replied = kOSBooleanTrue;
+    _IOServiceInterestNotifier *    notifier;
+    uint32_t                        msgIndex, msgRef, msgType;
+    IOReturn                        retCode;
+
+    memset(&msgArg, 0, sizeof(msgArg));
+    if (context->messageFilter &&
+        !context->messageFilter(context->us, object, context, &msgArg, 0))
+    {
+        if ((kIOLogDebugPower & gIOKitDebug) &&
+            (OSDynamicCast(_IOServiceInterestNotifier, object)))
+        {
+            _IOServiceInterestNotifier *n = (_IOServiceInterestNotifier *) object;
+            PM_LOG("%s DROP Client %s, notifier %p, handler %p\n",
+                context->us->getName(),
+                getIOMessageString(context->messageType),
+                object, n->handler);
+               }        
+        return;
+    }
+
+    notifier = OSDynamicCast(_IOServiceInterestNotifier, object);
+    msgType  = context->messageType;
+    msgIndex = context->responseArray->getCount();
+    msgRef   = ((context->serialNumber & 0xFFFF) << 16) + (msgIndex & 0xFFFF);
+
+    IOServicePM * pwrMgt = context->us->pwrMgt;
+    if (gIOKitDebug & kIOLogPower) {
+               OUR_PMLog(kPMLogClientNotify, msgRef, msgType);
+               if (OSDynamicCast(IOService, object)) {
+                       const char *who = ((IOService *) object)->getName();
+                       gPlatform->PMLog(who, kPMLogClientNotify, (uintptr_t) object, 0);
+               }
+        else if (notifier) {
+                       OUR_PMLog(kPMLogClientNotify, (uintptr_t) notifier->handler, 0);
+               }
+    }
+    if ((kIOLogDebugPower & gIOKitDebug) && notifier)
+    {
+        PM_LOG("%s MESG Client %s, notifier %p, handler %p\n",
+            context->us->getName(),
+            getIOMessageString(msgType),
+            object, notifier->handler);
+    }
+
+    msgArg.notifyRef = msgRef;
+    msgArg.maxWaitForReply = 0;
+
+    if (context->enableTracing && (notifier != 0))
+    {
+        uint32_t detail = ((msgIndex & 0xff) << 24) |
+                          ((msgType & 0xfff) << 12) |
+                          (((uintptr_t) notifier->handler) & 0xfff);
+        getPMRootDomain()->traceDetail( detail );
+    }
+
+    retCode = context->us->messageClient(
+        msgType, object, (void *) &msgArg, sizeof(msgArg));
+
+    if ( kIOReturnSuccess == retCode )
+    {
+        if ( 0 == msgArg.maxWaitForReply )
+        {
+            // client doesn't want time to respond
+                       OUR_PMLog(kPMLogClientAcknowledge, msgRef, (uintptr_t) object);
+        }
+        else
+        {
+            replied = kOSBooleanFalse;
+            if ( msgArg.maxWaitForReply > context->maxTimeRequested )
+            {
+                if (msgArg.maxWaitForReply > kCapabilityClientMaxWait)
+                {
+                    context->maxTimeRequested = kCapabilityClientMaxWait;
+                    PM_ERROR("%s: client %p returned %u for %s\n",
+                        context->us->getName(),
+                        notifier ? (void *) notifier->handler : object,
+                        msgArg.maxWaitForReply,
+                        getIOMessageString(msgType));
+                }
+                else
+                    context->maxTimeRequested = msgArg.maxWaitForReply;
+            }
+        }
+    }
+    else
+    {
+        // not a client of ours
+        // so we won't be waiting for response
+               OUR_PMLog(kPMLogClientAcknowledge, msgRef, 0);
+    }
+
+    context->responseArray->setObject(msgIndex, replied);
+}
 
 //*********************************************************************************
-// tellNoChangeDown
+// [public] tellNoChangeDown
 //
 // Notify registered applications and kernel clients that we are not
 // dropping power.
@@ -3557,12 +5647,11 @@ void tellClientWithResponse ( OSObject * object, void * context)
 
 void IOService::tellNoChangeDown ( unsigned long )
 {
-    return tellClients(kIOMessageDeviceWillNotPowerOff);
+    return tellClients( kIOMessageDeviceWillNotPowerOff );
 }
 
-
 //*********************************************************************************
-// tellChangeUp
+// [public] tellChangeUp
 //
 // Notify registered applications and kernel clients that we are raising power.
 //
@@ -3570,564 +5659,2106 @@ void IOService::tellNoChangeDown ( unsigned long )
 // the aborted destination state number.
 //*********************************************************************************
 
-void IOService::tellChangeUp ( unsigned long )
+void IOService::tellChangeUp ( unsigned long )
+{
+    return tellClients( kIOMessageDeviceHasPoweredOn );
+}
+
+//*********************************************************************************
+// [protected] tellClients
+//
+// Notify registered applications and kernel clients of something.
+//*********************************************************************************
+
+void IOService::tellClients ( int messageType )
+{
+    IOPMInterestContext     context;
+
+    RD_LOG("tellClients( %s )\n", getIOMessageString(messageType));
+
+    memset(&context, 0, sizeof(context));
+    context.messageType   = messageType;
+    context.isPreChange   = fIsPreChange;
+    context.us            = this;
+    context.stateNumber   = fHeadNotePowerState;
+    context.stateFlags    = fHeadNotePowerArrayEntry->capabilityFlags;
+    context.changeFlags   = fHeadNoteChangeFlags;
+    context.messageFilter = (IS_ROOT_DOMAIN) ?
+                            OSMemberFunctionCast(
+                                IOPMMessageFilter,
+                                this,
+                                &IOPMrootDomain::systemMessageFilter) : 0;
+
+    context.notifyType    = kNotifyPriority;
+    applyToInterested( gIOPriorityPowerStateInterest,
+        tellKernelClientApplier, (void *) &context );
+
+    context.notifyType    = kNotifyApps;
+    applyToInterested( gIOAppPowerStateInterest,
+        tellAppClientApplier, (void *) &context );
+
+    applyToInterested( gIOGeneralInterest,
+        tellKernelClientApplier, (void *) &context );
+}
+
+//*********************************************************************************
+// [private] tellKernelClientApplier
+//
+// Message a kernel client.
+//*********************************************************************************
+
+static void tellKernelClientApplier ( OSObject * object, void * arg )
+{
+    IOPowerStateChangeNotification     notify;
+    IOPMInterestContext *           context = (IOPMInterestContext *) arg;
+
+    if (context->messageFilter &&
+        !context->messageFilter(context->us, object, context, 0, 0))
+    {
+        if ((kIOLogDebugPower & gIOKitDebug) &&
+            (OSDynamicCast(_IOServiceInterestNotifier, object)))
+        {
+            _IOServiceInterestNotifier *n = (_IOServiceInterestNotifier *) object;
+            PM_LOG("%s DROP Client %s, notifier %p, handler %p\n",
+                context->us->getName(),
+                IOService::getIOMessageString(context->messageType),
+                object, n->handler);
+               }
+        return;
+    }
+
+    notify.powerRef     = (void *) 0;
+    notify.returnValue = 0;
+    notify.stateNumber = context->stateNumber;
+    notify.stateFlags  = context->stateFlags;
+
+    context->us->messageClient(context->messageType, object, &notify);
+
+    if ((kIOLogDebugPower & gIOKitDebug) &&
+        (OSDynamicCast(_IOServiceInterestNotifier, object)))
+    {
+        _IOServiceInterestNotifier *n = (_IOServiceInterestNotifier *) object;
+        PM_LOG("%s MESG Client %s, notifier %p, handler %p\n",
+            context->us->getName(),
+            IOService::getIOMessageString(context->messageType),
+            object, n->handler);
+    }
+}
+
+//*********************************************************************************
+// [private] tellAppClientApplier
+//
+// Message a registered application.
+//*********************************************************************************
+
+static void tellAppClientApplier ( OSObject * object, void * arg )
+{
+    IOPMInterestContext * context = (IOPMInterestContext *) arg;
+
+    if (context->messageFilter &&
+        !context->messageFilter(context->us, object, context, 0, 0))
+    {
+        if (kIOLogDebugPower & gIOKitDebug)
+        {
+            // Log client pid/name and client array index.
+            OSString * clientID = 0;
+            context->us->messageClient(kIOMessageCopyClientID, object, &clientID);
+            PM_LOG("%s DROP App %s, %s\n",
+                context->us->getName(),
+                IOService::getIOMessageString(context->messageType),
+                clientID ? clientID->getCStringNoCopy() : "");
+            if (clientID) clientID->release();
+        }
+        return;
+    }
+
+    if (kIOLogDebugPower & gIOKitDebug)
+    {
+        // Log client pid/name and client array index.
+        OSString * clientID = 0;
+        context->us->messageClient(kIOMessageCopyClientID, object, &clientID);
+        PM_LOG("%s MESG App %s, %s\n",
+            context->us->getName(),
+            IOService::getIOMessageString(context->messageType),
+            clientID ? clientID->getCStringNoCopy() : "");
+        if (clientID) clientID->release();
+    }
+
+    context->us->messageClient(context->messageType, object, 0);
+}
+
+//*********************************************************************************
+// [private] checkForDone
+//*********************************************************************************
+
+bool IOService::checkForDone ( void )
+{
+    int                        i = 0;
+    OSObject * theFlag;
+
+    if ( fResponseArray == NULL )
+    {
+        return true;
+    }
+    
+    for ( i = 0; ; i++ )
+    {
+        theFlag = fResponseArray->getObject(i);
+        if ( theFlag == NULL )
+        {
+            break;
+        }
+        if ( kOSBooleanTrue != theFlag ) 
+        {
+            return false;
+        }
+    }
+    return true;
+}
+
+//*********************************************************************************
+// [public] responseValid
+//*********************************************************************************
+
+bool IOService::responseValid ( uint32_t refcon, int pid )
+{
+    UInt16                     serialComponent;
+    UInt16                     ordinalComponent;
+    OSObject *         theFlag;
+
+    serialComponent  = (refcon >> 16) & 0xFFFF;
+    ordinalComponent = (refcon & 0xFFFF);
+
+    if ( serialComponent != fSerialNumber )
+    {
+        return false;
+    }
+    
+    if ( fResponseArray == NULL )
+    {
+        return false;
+    }
+    
+    theFlag = fResponseArray->getObject(ordinalComponent);
+    
+    if ( theFlag == 0 )
+    {
+        return false;
+    }
+
+    OSNumber * num;
+    if ((num = OSDynamicCast(OSNumber, theFlag)))
+    {
+#if LOG_APP_RESPONSE_TIMES
+        AbsoluteTime   now;
+        AbsoluteTime   start;
+        uint64_t        nsec;
+        OSString        *name = IOCopyLogNameForPID(pid);
+
+        clock_get_uptime(&now);
+        AbsoluteTime_to_scalar(&start) = num->unsigned64BitValue();
+        SUB_ABSOLUTETIME(&now, &start);
+        absolutetime_to_nanoseconds(now, &nsec);
+               
+        PMEventDetails *details = PMEventDetails::eventDetails(
+                                    kIOPMEventTypeAppResponse,                         // type
+                                    name ? name->getCStringNoCopy() : "",   // who
+                                    (uintptr_t)pid,                                                    // owner unique
+                                    NULL,                                                                      // interest name
+                                    0,                                                                         // old
+                                    0,                                                                         // new
+                                    0,                                                                         // result
+                                    NS_TO_US(nsec));                                           // usec completion time
+               
+        getPMRootDomain()->recordAndReleasePMEventGated( details );
+
+        if (kIOLogDebugPower & gIOKitDebug)
+        {
+            PM_LOG("Ack(%u) %u ms\n",
+                (uint32_t) ordinalComponent,
+                NS_TO_MS(nsec));
+        }
+
+        // > 100 ms
+        if (nsec > LOG_APP_RESPONSE_TIMES)
+        {
+            PM_LOG("PM response took %d ms (%s)\n", NS_TO_MS(nsec),
+                name ? name->getCStringNoCopy() : "");
+
+            if (nsec > LOG_APP_RESPONSE_MSG_TRACER)
+            {
+                // TODO: populate the messageType argument            
+                getPMRootDomain()->pmStatsRecordApplicationResponse(
+                    gIOPMStatsApplicationResponseSlow, 
+                    name ? name->getCStringNoCopy() : "", 0,
+                    NS_TO_MS(nsec), pid);
+            }            
+        }
+
+        if (name)
+            name->release();
+#endif
+        theFlag = kOSBooleanFalse;
+    }
+
+    if ( kOSBooleanFalse == theFlag ) 
+    {
+        fResponseArray->replaceObject(ordinalComponent, kOSBooleanTrue);
+    }
+    
+    return true;
+}
+
+//*********************************************************************************
+// [public] allowPowerChange
+//
+// Our power state is about to lower, and we have notified applications
+// and kernel clients, and one of them has acknowledged.  If this is the last to do
+// so, and all acknowledgements are positive, we continue with the power change.
+//*********************************************************************************
+
+IOReturn IOService::allowPowerChange ( unsigned long refcon )
+{
+       IOPMRequest * request;
+
+    if ( !initialized )
+    {
+        // we're unloading
+        return kIOReturnSuccess;
+    }
+
+       request = acquirePMRequest( this, kIOPMRequestTypeAllowPowerChange );
+       if (!request)
+               return kIOReturnNoMemory;
+
+       request->fArg0 = (void *) refcon;
+       request->fArg1 = (void *) proc_selfpid();
+       request->fArg2 = (void *) 0;
+       submitPMRequest( request );
+
+       return kIOReturnSuccess;
+}
+
+#ifndef __LP64__
+IOReturn IOService::serializedAllowPowerChange2 ( unsigned long refcon )
+{
+       // [deprecated] public
+       return kIOReturnUnsupported;
+}
+#endif /* !__LP64__ */
+
+//*********************************************************************************
+// [public] cancelPowerChange
+//
+// Our power state is about to lower, and we have notified applications
+// and kernel clients, and one of them has vetoed the change.  If this is the last
+// client to respond, we abandon the power change.
+//*********************************************************************************
+
+IOReturn IOService::cancelPowerChange ( unsigned long refcon )
+{
+       IOPMRequest *   request;
+    OSString *      name;
+
+    if ( !initialized )
+    {
+        // we're unloading
+        return kIOReturnSuccess;
+    }
+
+    name = IOCopyLogNameForPID(proc_selfpid());
+    PM_ERROR("PM notification cancel (%s)\n", name ? name->getCStringNoCopy() : "");
+
+       request = acquirePMRequest( this, kIOPMRequestTypeCancelPowerChange );
+       if (!request)
+    {
+        if (name)
+            name->release();
+        return kIOReturnNoMemory;
+    }
+
+    request->fArg0 = (void *) refcon;
+    request->fArg1 = (void *) proc_selfpid();
+    request->fArg2 = (void *) name;
+    submitPMRequest( request );
+
+    return kIOReturnSuccess;
+}
+
+#ifndef __LP64__
+IOReturn IOService::serializedCancelPowerChange2 ( unsigned long refcon )
+{
+       // [deprecated] public
+       return kIOReturnUnsupported;
+}
+
+//*********************************************************************************
+// PM_Clamp_Timer_Expired
+//
+// called when clamp timer expires...set power state to 0.
+//*********************************************************************************
+
+void IOService::PM_Clamp_Timer_Expired ( void )
+{
+}
+
+//*********************************************************************************
+// clampPowerOn
+//
+// Set to highest available power state for a minimum of duration milliseconds
+//*********************************************************************************
+
+void IOService::clampPowerOn ( unsigned long duration )
+{
+}
+#endif /* !__LP64__ */
+
+// MARK: -
+// MARK: Driver Overrides
+
+//*********************************************************************************
+// [public] setPowerState
+//
+// Does nothing here.  This should be implemented in a subclass driver.
+//*********************************************************************************
+
+IOReturn IOService::setPowerState (
+       unsigned long powerStateOrdinal, IOService * whatDevice )
+{
+    return IOPMNoErr;
+}
+
+//*********************************************************************************
+// [public] maxCapabilityForDomainState
+//
+// Finds the highest power state in the array whose input power
+// requirement is equal to the input parameter.  Where a more intelligent
+// decision is possible, override this in the subclassed driver.
+//*********************************************************************************
+
+unsigned long IOService::maxCapabilityForDomainState ( IOPMPowerFlags domainState )
+{
+   int i;
+
+   if (fNumberOfPowerStates == 0 )
+   {
+       return 0;
+   }
+   for ( i = fNumberOfPowerStates - 1; i >= 0; i-- )
+   {
+       if ( (domainState & fPowerStates[i].inputPowerFlags) ==
+                                      fPowerStates[i].inputPowerFlags )
+       {
+           return i;
+       }
+   }
+   return 0;
+}
+
+//*********************************************************************************
+// [public] initialPowerStateForDomainState
+//
+// Finds the highest power state in the array whose input power
+// requirement is equal to the input parameter.  Where a more intelligent
+// decision is possible, override this in the subclassed driver.
+//*********************************************************************************
+
+unsigned long IOService::initialPowerStateForDomainState ( IOPMPowerFlags domainState )
+{
+    int i;
+
+    if (fNumberOfPowerStates == 0 )
+    {
+        return 0;
+    }
+    for ( i = fNumberOfPowerStates - 1; i >= 0; i-- )
+    {
+        if ( (domainState & fPowerStates[i].inputPowerFlags) ==
+                       fPowerStates[i].inputPowerFlags )
+        {
+            return i;
+        }
+    }
+    return 0;
+}
+
+//*********************************************************************************
+// [public] powerStateForDomainState
+//
+// Finds the highest power state in the array whose input power
+// requirement is equal to the input parameter.  Where a more intelligent
+// decision is possible, override this in the subclassed driver.
+//*********************************************************************************
+
+unsigned long IOService::powerStateForDomainState ( IOPMPowerFlags domainState )
+{
+    int i;
+
+    if (fNumberOfPowerStates == 0 )
+    {
+        return 0;
+    }
+    for ( i = fNumberOfPowerStates - 1; i >= 0; i-- )
+    {
+        if ( (domainState & fPowerStates[i].inputPowerFlags) ==
+                       fPowerStates[i].inputPowerFlags )
+        {
+            return i;
+        }
+    }
+    return 0;
+}
+
+#ifndef __LP64__
+//*********************************************************************************
+// [deprecated] didYouWakeSystem
+//
+// Does nothing here.  This should be implemented in a subclass driver.
+//*********************************************************************************
+
+bool IOService::didYouWakeSystem ( void )
+{
+    return false;
+}
+#endif /* !__LP64__ */
+
+//*********************************************************************************
+// [public] powerStateWillChangeTo
+//
+// Does nothing here.  This should be implemented in a subclass driver.
+//*********************************************************************************
+
+IOReturn IOService::powerStateWillChangeTo ( IOPMPowerFlags, unsigned long, IOService * )
+{
+    return kIOPMAckImplied;
+}
+
+//*********************************************************************************
+// [public] powerStateDidChangeTo
+//
+// Does nothing here.  This should be implemented in a subclass driver.
+//*********************************************************************************
+
+IOReturn IOService::powerStateDidChangeTo ( IOPMPowerFlags, unsigned long, IOService * )
+{
+    return kIOPMAckImplied;
+}
+
+//*********************************************************************************
+// [protected] powerChangeDone
+//
+// Called from PM work loop thread.
+// Does nothing here.  This should be implemented in a subclass policy-maker.
+//*********************************************************************************
+
+void IOService::powerChangeDone ( unsigned long )
+{
+}
+
+#ifndef __LP64__
+//*********************************************************************************
+// [deprecated] newTemperature
+//
+// Does nothing here.  This should be implemented in a subclass driver.
+//*********************************************************************************
+
+IOReturn IOService::newTemperature ( long currentTemp, IOService * whichZone )
+{
+    return IOPMNoErr;
+}
+#endif /* !__LP64__ */
+
+//*********************************************************************************
+// [public] systemWillShutdown
+//
+// System shutdown and restart notification.
+//*********************************************************************************
+
+void IOService::systemWillShutdown( IOOptionBits specifier )
+{
+       IOPMrootDomain * rootDomain = IOService::getPMRootDomain();
+       if (rootDomain)
+               rootDomain->acknowledgeSystemWillShutdown( this );
+}
+
+// MARK: -
+// MARK: PM State Machine
+
+//*********************************************************************************
+// [private static] acquirePMRequest
+//*********************************************************************************
+
+IOPMRequest *
+IOService::acquirePMRequest( IOService * target, IOOptionBits requestType,
+                             IOPMRequest * active )
+{
+       IOPMRequest * request;
+
+       assert(target);
+
+       request = IOPMRequest::create();
+       if (request)
+       {
+               request->init( target, requestType );
+        if (active)
+        {
+            IOPMRequest * root = active->getRootRequest();
+            if (root) request->attachRootRequest(root);
+        }
+    }
+       else
+       {
+        PM_ERROR("%s: No memory for PM request type 0x%x\n",
+            target->getName(), (uint32_t) requestType);
+       }
+       return request;
+}
+
+//*********************************************************************************
+// [private static] releasePMRequest
+//*********************************************************************************
+
+void IOService::releasePMRequest( IOPMRequest * request )
+{
+       if (request)
+       {
+               request->reset();
+               request->release();
+       }
+}
+
+//*********************************************************************************
+// [private] submitPMRequest
+//*********************************************************************************
+
+void IOService::submitPMRequest( IOPMRequest * request )
+{
+       assert( request );
+       assert( gIOPMReplyQueue );
+       assert( gIOPMRequestQueue );
+
+       PM_LOG1("[+ %02lx] %p [%p %s] %p %p %p\n",
+               (long)request->getType(), request,
+               request->getTarget(), request->getTarget()->getName(),
+               request->fArg0, request->fArg1, request->fArg2);
+
+       if (request->isReplyType())
+               gIOPMReplyQueue->queuePMRequest( request );
+       else
+               gIOPMRequestQueue->queuePMRequest( request );
+}
+
+void IOService::submitPMRequest( IOPMRequest ** requests, IOItemCount count )
+{
+       assert( requests );
+       assert( count > 0 );
+       assert( gIOPMRequestQueue );
+
+       for (IOItemCount i = 0; i < count; i++)
+       {
+               IOPMRequest * req = requests[i];
+               PM_LOG1("[+ %02lx] %p [%p %s] %p %p %p\n",
+                       (long)req->getType(), req,
+                       req->getTarget(), req->getTarget()->getName(),
+                       req->fArg0, req->fArg1, req->fArg2);
+       }
+
+       gIOPMRequestQueue->queuePMRequestChain( requests, count );
+}
+
+//*********************************************************************************
+// [private] servicePMRequestQueue
+//
+// Called from IOPMRequestQueue::checkForWork().
+//*********************************************************************************
+
+bool IOService::servicePMRequestQueue(
+       IOPMRequest *           request,
+       IOPMRequestQueue *      queue )
+{
+    bool more;
+
+    if (initialized)
+    {
+        // Work queue will immediately execute the queue'd request if possible.
+        // If execution blocks, the work queue will wait for a producer signal.
+        // Only need to signal more when completing attached requests.
+
+        more = gIOPMWorkQueue->queuePMRequest(request, pwrMgt);
+        return more;
+    }
+
+    // Calling PM without PMinit() is not allowed, fail the request.
+
+    PM_LOG("%s: PM not initialized\n", getName());
+       fAdjustPowerScheduled = false;
+       more = gIOPMFreeQueue->queuePMRequest(request);
+    if (more) gIOPMWorkQueue->incrementProducerCount();
+       return more;
+}
+
+//*********************************************************************************
+// [private] servicePMFreeQueue
+//
+// Called from IOPMCompletionQueue::checkForWork().
+//*********************************************************************************
+
+bool IOService::servicePMFreeQueue(
+       IOPMRequest *             request,
+       IOPMCompletionQueue * queue )
+{
+       bool            more = request->getNextRequest();
+    IOPMRequest *   root = request->getRootRequest();
+
+    if (root && (root != request))
+        more = true;
+    if (more)
+        gIOPMWorkQueue->incrementProducerCount();
+
+       releasePMRequest( request );
+       return more;
+}
+
+//*********************************************************************************
+// [private] retirePMRequest
+//
+// Called by IOPMWorkQueue to retire a completed request.
+//*********************************************************************************
+
+bool IOService::retirePMRequest( IOPMRequest * request, IOPMWorkQueue * queue )
+{
+       assert(request && queue);
+
+       PM_LOG1("[- %02x] %p [%p %s] state %d, busy %d\n",
+               request->getType(), request, this, getName(),
+               fMachineState, gIOPMBusyCount);
+
+       // Catch requests created by idleTimerExpired().
+
+       if ((request->getType() == kIOPMRequestTypeActivityTickle) &&
+           (request->fArg1 == (void *) (uintptr_t) false))
+       {
+               // Idle timer power drop request completed.
+               // Restart the idle timer if deviceDesire can go lower, otherwise set
+               // a flag so we know to restart idle timer when deviceDesire goes up.
+
+               if (fDeviceDesire > 0)
+               {
+            fActivityTickleCount = 0;
+                       clock_get_uptime(&fIdleTimerStartTime);
+                       start_PM_idle_timer();
+               }
+               else
+                       fIdleTimerStopped = true;
+       }
+
+    // If the request is linked, then Work queue has already incremented its
+    // producer count.
+
+       return (gIOPMFreeQueue->queuePMRequest( request ));
+}
+
+//*********************************************************************************
+// [private] isPMBlocked
+//
+// Check if machine state transition is blocked.
+//*********************************************************************************
+
+bool IOService::isPMBlocked ( IOPMRequest * request, int count )
+{
+       int     reason = 0;
+
+       do {
+               if (kIOPM_Finished == fMachineState)
+                       break;
+
+               if (kIOPM_DriverThreadCallDone == fMachineState)
+               {
+            // 5 = kDriverCallInformPreChange
+            // 6 = kDriverCallInformPostChange
+            // 7 = kDriverCallSetPowerState
+                       if (fDriverCallBusy)
+                reason = 5 + fDriverCallReason;
+                       break;
+               }
+
+               // Waiting on driver's setPowerState() timeout.
+               if (fDriverTimer)
+               {
+                       reason = 1; break;
+               }
+
+               // Child or interested driver acks pending.
+               if (fHeadNotePendingAcks)
+               {
+                       reason = 2; break;
+               }
+
+               // Waiting on apps or priority power interest clients.
+               if (fResponseArray)
+               {
+                       reason = 3; break;
+               }
+
+               // Waiting on settle timer expiration.
+               if (fSettleTimeUS)
+               {
+                       reason = 4; break;
+               }
+       } while (false);
+
+       fWaitReason = reason;
+
+       if (reason)
+       {
+               if (count)
+               {
+                       PM_LOG1("[B %02x] %p [%p %s] state %d, reason %d\n",
+                               request->getType(), request, this, getName(),
+                               fMachineState, reason);
+               }
+
+               return true;
+       }
+
+       return false;
+}
+
+//*********************************************************************************
+// [private] servicePMRequest
+//
+// Service a request from our work queue.
+//*********************************************************************************
+
+bool IOService::servicePMRequest( IOPMRequest * request, IOPMWorkQueue * queue )
+{
+       bool    done = false;
+       int             loop = 0;
+
+       assert(request && queue);
+
+       while (isPMBlocked(request, loop++) == false)
+       {
+               PM_LOG1("[W %02x] %p [%p %s] state %d\n",
+                       request->getType(), request, this, getName(), fMachineState);
+
+               gIOPMRequest = request;
+        gIOPMWorkCount++;
+
+               // Every PM machine states must be handled in one of the cases below.
+
+               switch ( fMachineState )
+               {
+                       case kIOPM_Finished:
+                               executePMRequest( request );
+                               break;
+
+                       case kIOPM_OurChangeTellClientsPowerDown:
+                // Root domain might self cancel due to assertions.
+                if (IS_ROOT_DOMAIN)
+                {
+                    bool cancel = (bool) fDoNotPowerDown;
+                    getPMRootDomain()->askChangeDownDone(
+                        &fHeadNoteChangeFlags, &cancel);
+                    fDoNotPowerDown = cancel;
+                }
+
+                // askChangeDown() done, was it vetoed?
+                               if (!fDoNotPowerDown)
+                               {
+                    if (IS_ROOT_DOMAIN) {
+                        PMEventDetails *details = PMEventDetails::eventDetails(
+                                                    kIOPMEventTypeAppNotificationsFinished,
+                                                    NULL,
+                                                    0,
+                                                    0);
+                                               
+                                               getPMRootDomain()->recordAndReleasePMEventGated( details );
+                    }
+
+                                       // no, we can continue
+                                       OurChangeTellClientsPowerDown();
+                               }
+                               else
+                               {
+                    if (IS_ROOT_DOMAIN) {
+                        PMEventDetails *details = PMEventDetails::eventDetails(
+                                                    kIOPMEventTypeSleepDone,
+                                                    NULL,
+                                                    1, /* reason: 1 == Ask clients succeeded */
+                                                    kIOReturnAborted); /* result */
+                         
+                        getPMRootDomain()->recordAndReleasePMEventGated( details );
+                    }
+
+                                       OUR_PMLog(kPMLogIdleCancel, (uintptr_t) this, fMachineState);
+                                       PM_ERROR("%s: idle cancel\n", fName);
+                                       // yes, rescind the warning
+                                       tellNoChangeDown(fHeadNotePowerState);
+                                       // mark the change note un-actioned
+                                       fHeadNoteChangeFlags |= kIOPMNotDone;
+                                       // and we're done
+                                       OurChangeFinish();
+                               }
+                               break;
+
+                       case kIOPM_OurChangeTellPriorityClientsPowerDown:
+                               // tellChangeDown(kNotifyApps) done, was it cancelled?
+                               if (fDoNotPowerDown)
+                               {
+                    if (IS_ROOT_DOMAIN) {
+                                               PMEventDetails *details = PMEventDetails::eventDetails(
+                                                    kIOPMEventTypeSleepDone,
+                                                    NULL,
+                                                    2, /* reason: 2 == Client cancelled wake */
+                                                    kIOReturnAborted); /* result */
+                                               
+                                               getPMRootDomain()->recordAndReleasePMEventGated( details );
+                    }
+                                       OUR_PMLog(kPMLogIdleCancel, (uintptr_t) this, fMachineState);
+                                       PM_ERROR("%s: idle revert\n", fName);
+                                       // no, tell clients we're back in the old state
+                                       tellChangeUp(fCurrentPowerState);
+                                       // mark the change note un-actioned
+                                       fHeadNoteChangeFlags |= kIOPMNotDone;
+                                       // and we're done
+                                       OurChangeFinish();
+                               }
+                               else
+                               {
+                    if (IS_ROOT_DOMAIN) {
+                                               PMEventDetails *details = PMEventDetails::eventDetails(
+                                                    kIOPMEventTypeAppNotificationsFinished,
+                                                    NULL,
+                                                    2, /* reason: 2 == TellPriorityClientsDone */                                                                                                                                      
+                                                    kIOReturnSuccess); /* result */
+                                               
+                                               getPMRootDomain()->recordAndReleasePMEventGated( details );
+                    }
+                                       // yes, we can continue
+                                       OurChangeTellPriorityClientsPowerDown();  
+                               }
+                               break;
+
+                       case kIOPM_OurChangeNotifyInterestedDriversWillChange:
+                               OurChangeNotifyInterestedDriversWillChange();
+                               break;
+
+                       case kIOPM_OurChangeSetPowerState:
+                               OurChangeSetPowerState();
+                               break;
+
+                       case kIOPM_OurChangeWaitForPowerSettle:
+                               OurChangeWaitForPowerSettle();
+                               break;
+
+                       case kIOPM_OurChangeNotifyInterestedDriversDidChange:
+                               OurChangeNotifyInterestedDriversDidChange();
+                               break;
+
+            case kIOPM_OurChangeTellCapabilityDidChange:
+                OurChangeTellCapabilityDidChange();
+                break;
+
+                       case kIOPM_OurChangeFinish:
+                               OurChangeFinish();
+                               break;
+
+                       case kIOPM_ParentChangeTellPriorityClientsPowerDown:
+                               ParentChangeTellPriorityClientsPowerDown();
+                               break;
+
+                       case kIOPM_ParentChangeNotifyInterestedDriversWillChange:
+                               ParentChangeNotifyInterestedDriversWillChange();
+                               break;
+
+                       case kIOPM_ParentChangeSetPowerState:
+                               ParentChangeSetPowerState();
+                               break;
+
+                       case kIOPM_ParentChangeWaitForPowerSettle:
+                               ParentChangeWaitForPowerSettle();
+                               break;
+
+                       case kIOPM_ParentChangeNotifyInterestedDriversDidChange:
+                               ParentChangeNotifyInterestedDriversDidChange();
+                               break;
+
+            case kIOPM_ParentChangeTellCapabilityDidChange:
+                ParentChangeTellCapabilityDidChange();
+                break;
+
+                       case kIOPM_ParentChangeAcknowledgePowerChange:
+                               ParentChangeAcknowledgePowerChange();
+                               break;
+
+                       case kIOPM_DriverThreadCallDone:
+                               if (fDriverCallReason == kDriverCallSetPowerState)
+                                       notifyControllingDriverDone();
+                               else
+                                       notifyInterestedDriversDone();
+                               break;
+
+                       case kIOPM_NotifyChildrenOrdered:
+                               notifyChildrenOrdered();
+                               break;
+
+                       case kIOPM_NotifyChildrenDelayed:
+                               notifyChildrenDelayed();
+                               break;
+
+            case kIOPM_NotifyChildrenStart:
+                PM_LOG2("%s: kIOPM_NotifyChildrenStart done\n", getName());
+                MS_POP();   // from notifyInterestedDriversDone()
+                notifyChildren();
+                break;
+
+            case kIOPM_SyncTellClientsPowerDown:
+                // Root domain might self cancel due to assertions.
+                if (IS_ROOT_DOMAIN)
+                {
+                    bool cancel = (bool) fDoNotPowerDown;
+                    getPMRootDomain()->askChangeDownDone(
+                        &fHeadNoteChangeFlags, &cancel);
+                    fDoNotPowerDown = cancel;
+                }                
+                               if (!fDoNotPowerDown)
+                               {
+                    fMachineState = kIOPM_SyncTellPriorityClientsPowerDown;
+                    fOutOfBandParameter = kNotifyApps;
+                    tellChangeDown(fHeadNotePowerState);
+                               }
+                               else
+                               {
+                                       OUR_PMLog(kPMLogIdleCancel, (uintptr_t) this, fMachineState);
+                                       PM_ERROR("%s: idle cancel\n", fName);
+                                       tellNoChangeDown(fHeadNotePowerState);
+                                       fHeadNoteChangeFlags |= kIOPMNotDone;
+                                       OurChangeFinish();
+                               }
+                break;
+
+            case kIOPM_SyncTellPriorityClientsPowerDown:
+                               if (!fDoNotPowerDown)
+                               {
+                    fMachineState = kIOPM_SyncNotifyWillChange;
+                    fOutOfBandParameter = kNotifyPriority;
+                    tellChangeDown(fHeadNotePowerState);
+                }
+                else
+                {
+                                       OUR_PMLog(kPMLogIdleCancel, (uintptr_t) this, fMachineState);
+                                       PM_ERROR("%s: idle revert\n", fName);
+                                       tellChangeUp(fCurrentPowerState);
+                                       fHeadNoteChangeFlags |= kIOPMNotDone;
+                                       OurChangeFinish();
+                               }
+                               break;
+
+            case kIOPM_SyncNotifyWillChange:
+                if (kIOPMSyncNoChildNotify & fHeadNoteChangeFlags)
+                {
+                    fMachineState = kIOPM_SyncFinish;
+                    continue;
+                }
+                fMachineState     = kIOPM_SyncNotifyDidChange;
+                fDriverCallReason = kDriverCallInformPreChange;
+                notifyChildren();
+                break;
+
+            case kIOPM_SyncNotifyDidChange:
+                fIsPreChange = false;
+
+                if (fHeadNoteChangeFlags & kIOPMParentInitiated)
+                    fMachineState = kIOPM_SyncFinish;
+                else
+                    fMachineState = kIOPM_SyncTellCapabilityDidChange;
+
+                fDriverCallReason = kDriverCallInformPostChange;
+                notifyChildren();
+                break;
+
+            case kIOPM_SyncTellCapabilityDidChange:
+                tellSystemCapabilityChange( kIOPM_SyncFinish );
+                break;
+
+            case kIOPM_SyncFinish:
+                if (fHeadNoteChangeFlags & kIOPMParentInitiated)
+                    ParentChangeAcknowledgePowerChange();
+                else
+                    OurChangeFinish();
+                break;
+
+            case kIOPM_TellCapabilityChangeDone:
+                if (fIsPreChange)
+                {
+                    if (fOutOfBandParameter == kNotifyCapabilityChangePriority)
+                    {
+                        MS_POP();   // tellSystemCapabilityChange()
+                        continue;
+                    }
+                    fOutOfBandParameter = kNotifyCapabilityChangePriority;
+                }
+                else
+                {
+                    if (fOutOfBandParameter == kNotifyCapabilityChangeApps)
+                    {
+                        MS_POP();   // tellSystemCapabilityChange()
+                        continue;
+                    }
+                    fOutOfBandParameter = kNotifyCapabilityChangeApps;
+                }
+                tellClientsWithResponse( fOutOfBandMessage );
+                break;
+
+                       default:
+                               panic("servicePMWorkQueue: unknown machine state %x",
+                    fMachineState);
+               }
+
+               gIOPMRequest = 0;
+
+               if (fMachineState == kIOPM_Finished)
+               {
+                       done = true;
+                       break;
+               }
+       }
+
+       return done;
+}
+
+//*********************************************************************************
+// [private] executePMRequest
+//*********************************************************************************
+
+void IOService::executePMRequest( IOPMRequest * request )
+{
+       assert( kIOPM_Finished == fMachineState );
+
+       switch (request->getType())
+       {
+               case kIOPMRequestTypePMStop:
+                       handlePMstop( request );
+                       break;
+
+               case kIOPMRequestTypeAddPowerChild1:
+                       addPowerChild1( request );
+                       break;
+
+               case kIOPMRequestTypeAddPowerChild2:
+                       addPowerChild2( request );
+                       break;
+
+               case kIOPMRequestTypeAddPowerChild3:
+                       addPowerChild3( request );
+                       break;
+
+               case kIOPMRequestTypeRegisterPowerDriver:
+                       handleRegisterPowerDriver( request );
+                       break;
+
+               case kIOPMRequestTypeAdjustPowerState:
+                       fAdjustPowerScheduled = false;
+                       rebuildChildClampBits();
+                       adjustPowerState();
+                       break;
+
+               case kIOPMRequestTypePowerDomainWillChange:
+                       handlePowerDomainWillChangeTo( request );
+                       break;
+
+               case kIOPMRequestTypePowerDomainDidChange:
+            
+                       handlePowerDomainDidChangeTo( request );
+                       break;
+
+               case kIOPMRequestTypeRequestPowerState:
+        case kIOPMRequestTypeRequestPowerStateOverride:
+                       handleRequestPowerState( request );
+                       break;
+
+               case kIOPMRequestTypePowerOverrideOnPriv:
+               case kIOPMRequestTypePowerOverrideOffPriv:
+                       handlePowerOverrideChanged( request );
+                       break;
+
+               case kIOPMRequestTypeActivityTickle:
+                       handleActivityTickle( request );
+                       break;
+
+        case kIOPMRequestTypeSynchronizePowerTree:
+                       handleSynchronizePowerTree( request );
+                       break;
+
+        case kIOPMRequestTypeSetIdleTimerPeriod:
+            {
+                fIdleTimerPeriod = (uintptr_t) request->fArg0;
+
+                if ((false == fLockedFlags.PMStop) && (fIdleTimerPeriod > 0))
+                {
+                    fActivityTickleCount = 0;
+                    clock_get_uptime(&fIdleTimerStartTime);
+                    start_PM_idle_timer();
+                }
+            }
+            break;
+
+               default:
+                       panic("executePMRequest: unknown request type %x", request->getType());
+       }
+}
+
+//*********************************************************************************
+// [private] servicePMReplyQueue
+//*********************************************************************************
+
+bool IOService::servicePMReplyQueue( IOPMRequest * request, IOPMRequestQueue * queue )
+{
+       bool more = false;
+
+       assert( request && queue );
+       assert( request->isReplyType() );
+
+       PM_LOG1("[A %02x] %p [%p %s] state %d\n",
+               request->getType(), request, this, getName(), fMachineState);
+
+       switch ( request->getType() )
+       {
+               case kIOPMRequestTypeAllowPowerChange:
+               case kIOPMRequestTypeCancelPowerChange:
+                       // Check if we are expecting this response.
+                       if (responseValid((uint32_t)(uintptr_t) request->fArg0,
+                              (int)(uintptr_t) request->fArg1))
+                       {
+                               if (kIOPMRequestTypeCancelPowerChange == request->getType())
+                {
+                    // Clients are not allowed to cancel when kIOPMSkipAskPowerDown
+                    // flag is set. Only root domain will set this flag.
+
+                    if ((fHeadNoteChangeFlags & kIOPMSkipAskPowerDown) == 0)
+                    {
+                        fDoNotPowerDown = true;
+
+                        OSString * name = (OSString *) request->fArg2;
+                        getPMRootDomain()->pmStatsRecordApplicationResponse(
+                            gIOPMStatsApplicationResponseCancel,
+                            name ? name->getCStringNoCopy() : "", 0,
+                            0, (int)(uintptr_t) request->fArg1);
+                    }
+                }
+
+                               if (checkForDone())
+                               {
+                                       stop_ack_timer();
+                    cleanClientResponses(false);
+                                       more = true;
+                               }
+                       }
+            // OSString containing app name in Arg2 must be released.
+            if (request->getType() == kIOPMRequestTypeCancelPowerChange)
+            {
+                OSObject * obj = (OSObject *) request->fArg2;
+                if (obj) obj->release();
+            }
+                       break;
+
+               case kIOPMRequestTypeAckPowerChange:
+                       more = handleAcknowledgePowerChange( request );
+                       break;
+
+               case kIOPMRequestTypeAckSetPowerState:
+                       if (fDriverTimer == -1)
+                       {
+                               // driver acked while setPowerState() call is in-flight.
+                               // take this ack, return value from setPowerState() is irrelevant.
+                               OUR_PMLog(kPMLogDriverAcknowledgeSet,
+                                       (uintptr_t) this, fDriverTimer);
+                               fDriverTimer = 0;
+                       }
+                       else if (fDriverTimer > 0)
+                       {
+                               // expected ack, stop the timer
+                               stop_ack_timer();
+
+#if LOG_SETPOWER_TIMES
+                uint64_t nsec = computeTimeDeltaNS(&fDriverCallStartTime);
+                if (nsec > LOG_SETPOWER_TIMES)
+                    PM_LOG("%s::setPowerState(%p, %lu -> %lu) async took %d ms\n",
+                        fName, this, fCurrentPowerState, fHeadNotePowerState, NS_TO_MS(nsec));
+                               
+                               PMEventDetails *details = PMEventDetails::eventDetails(
+                                            kIOPMEventTypeSetPowerStateDelayed,                // type
+                                            fName,                                                                     // who
+                                            (uintptr_t)this,                                           // owner unique
+                                            NULL,                                                                      // interest name
+                                            (uint8_t)getPowerState(),                          // old
+                                            (uint8_t)fHeadNotePowerState,                      // new
+                                            0,                                                                         // result
+                                            NS_TO_US(nsec));                                           // usec completion time
+                               
+                               getPMRootDomain()->recordAndReleasePMEventGated( details );
+#endif
+                               OUR_PMLog(kPMLogDriverAcknowledgeSet, (uintptr_t) this, fDriverTimer);
+                               fDriverTimer = 0;
+                               more = true;
+                       }
+                       else
+                       {
+                               // unexpected ack
+                               OUR_PMLog(kPMLogAcknowledgeErr4, (uintptr_t) this, 0);
+                       }
+                       break;
+
+               case kIOPMRequestTypeInterestChanged:
+                       handleInterestChanged( request );
+                       more = true;
+                       break;
+
+               case kIOPMRequestTypeIdleCancel:
+                       if ((fMachineState == kIOPM_OurChangeTellClientsPowerDown) 
+             || (fMachineState == kIOPM_OurChangeTellPriorityClientsPowerDown) 
+             || (fMachineState == kIOPM_SyncTellClientsPowerDown)
+             || (fMachineState == kIOPM_SyncTellPriorityClientsPowerDown))
+                       {
+                               OUR_PMLog(kPMLogIdleCancel, (uintptr_t) this, fMachineState);
+                PM_LOG2("%s: cancel from machine state %d\n",
+                    getName(), fMachineState);
+                               fDoNotPowerDown = true;
+                // Stop waiting for app replys.
+                               if ((fMachineState == kIOPM_OurChangeTellPriorityClientsPowerDown) ||
+                    (fMachineState == kIOPM_SyncTellPriorityClientsPowerDown))
+                                       cleanClientResponses(false);
+                               more = true;
+                       }
+                       break;
+
+        case kIOPMRequestTypeChildNotifyDelayCancel:
+            if (fMachineState == kIOPM_NotifyChildrenDelayed)
+            {
+                PM_LOG2("%s: delay notify cancelled\n", getName());                
+                notifyChildrenDelayed();
+            }
+            break;
+
+               default:
+                       panic("servicePMReplyQueue: unknown reply type %x",
+                request->getType());
+       }
+
+       more |= gIOPMFreeQueue->queuePMRequest(request);
+    if (more)
+        gIOPMWorkQueue->incrementProducerCount();
+
+       return more;
+}
+
+//*********************************************************************************
+// [private] assertPMDriverCall / deassertPMDriverCall
+//*********************************************************************************
+
+bool IOService::assertPMDriverCall(
+    IOPMDriverCallEntry *   entry,
+    IOOptionBits            options,
+    IOPMinformee *          inform )
+{
+    IOService * target = 0;
+    bool        ok = false;
+
+    if (!initialized)
+        return false;
+
+    PM_LOCK();
+
+    if (fLockedFlags.PMStop)
+    {
+        goto fail;
+    }
+    
+    if (((options & kIOPMADC_NoInactiveCheck) == 0) && isInactive())
+    {
+        goto fail;
+    }
+
+    if (inform)
+    {
+        if (!inform->active)
+        {
+            goto fail;
+        }
+        target = inform->whatObject;
+        if (target->isInactive())
+        {
+            goto fail;
+        }
+    }
+
+    entry->thread = current_thread();
+    entry->target = target;
+    queue_enter(&fPMDriverCallQueue, entry, IOPMDriverCallEntry *, link);
+    ok = true;
+
+fail:
+    PM_UNLOCK();
+
+    return ok;
+}
+
+void IOService::deassertPMDriverCall( IOPMDriverCallEntry * entry )
+{
+    bool wakeup = false;
+
+    PM_LOCK();
+
+    assert( !queue_empty(&fPMDriverCallQueue) );
+    queue_remove(&fPMDriverCallQueue, entry, IOPMDriverCallEntry *, link);
+    if (fLockedFlags.PMDriverCallWait)
+    {
+        wakeup = true;
+    }
+
+    PM_UNLOCK();
+
+    if (wakeup)
+        PM_LOCK_WAKEUP(&fPMDriverCallQueue);
+}
+
+void IOService::waitForPMDriverCall( IOService * target )
 {
-    return tellClients(kIOMessageDeviceHasPoweredOn);
-}
+    const IOPMDriverCallEntry * entry;
+    thread_t                    thread = current_thread();
+    AbsoluteTime                deadline;
+    int                         waitResult;
+    bool                        log = true;
+    bool                        wait;
+
+    do {
+        wait = false;
+        queue_iterate(&fPMDriverCallQueue, entry, const IOPMDriverCallEntry *, link)
+        {
+            // Target of interested driver call
+            if (target && (target != entry->target))
+                continue;
+
+            if (entry->thread == thread)
+            {
+                if (log)
+                {
+                    PM_LOG("%s: %s(%s) on PM thread\n",
+                        fName, __FUNCTION__, target ? target->getName() : "");
+                    OSReportWithBacktrace("%s: %s(%s) on PM thread\n",
+                        fName, __FUNCTION__, target ? target->getName() : "");
+                    log = false;
+                }
+                continue;
+            }
+            
+            wait = true;
+            break;
+        }
 
+        if (wait)
+        {
+            fLockedFlags.PMDriverCallWait = true;
+            clock_interval_to_deadline(15, kSecondScale, &deadline);
+            waitResult = PM_LOCK_SLEEP(&fPMDriverCallQueue, deadline);
+            fLockedFlags.PMDriverCallWait = false;
+            if (THREAD_TIMED_OUT == waitResult)
+            {
+                PM_ERROR("%s: waitForPMDriverCall timeout\n", fName);
+                wait = false;
+            }
+        }
+    } while (wait);
+}
 
 //*********************************************************************************
-// tellClients
-//
-// Notify registered applications and kernel clients of something.
+// [private] Debug helpers
 //*********************************************************************************
 
-void IOService::tellClients ( int messageType )
+const char * IOService::getIOMessageString( uint32_t msg )
 {
-    struct context theContext;
-
-    theContext.msgType = messageType;
-    theContext.us = this;
-    theContext.stateNumber = priv->head_note_state;
-    theContext.stateFlags = priv->head_note_capabilityFlags;
+#define MSG_ENTRY(x)    {x, #x}
+
+    static const IONamedValue msgNames[] = { 
+        MSG_ENTRY( kIOMessageCanDevicePowerOff      ),
+        MSG_ENTRY( kIOMessageDeviceWillPowerOff     ),
+        MSG_ENTRY( kIOMessageDeviceWillNotPowerOff  ),
+        MSG_ENTRY( kIOMessageDeviceHasPoweredOn     ),
+        MSG_ENTRY( kIOMessageCanSystemPowerOff      ),
+        MSG_ENTRY( kIOMessageSystemWillPowerOff     ),
+        MSG_ENTRY( kIOMessageSystemWillNotPowerOff  ),
+        MSG_ENTRY( kIOMessageCanSystemSleep         ),
+        MSG_ENTRY( kIOMessageSystemWillSleep        ),
+        MSG_ENTRY( kIOMessageSystemWillNotSleep     ),
+        MSG_ENTRY( kIOMessageSystemHasPoweredOn     ),
+        MSG_ENTRY( kIOMessageSystemWillRestart      ),
+        MSG_ENTRY( kIOMessageSystemWillPowerOn      ),
+        MSG_ENTRY( kIOMessageSystemCapabilityChange )
+    };
 
-    applyToInterested(gIOAppPowerStateInterest,tellClient,(void *)&theContext);
-    applyToInterested(gIOGeneralInterest,tellClient,(void *)&theContext);
+    return IOFindNameForValue(msg, msgNames);
 }
 
+// MARK: -
+// MARK: IOPMRequest
 
 //*********************************************************************************
-// tellClient
+// IOPMRequest Class
 //
-// Notify a registered application or kernel client of something.
+// Requests from PM clients, and also used for inter-object messaging within PM.
 //*********************************************************************************
-void tellClient ( OSObject * object, void * context)
-{
-    struct context *                   theContext = (struct context *)context;
-    IOPowerStateChangeNotification     notify;
 
-    notify.powerRef    = (void *) 0;
-    notify.returnValue = 0;
-    notify.stateNumber = theContext->stateNumber;
-    notify.stateFlags  = theContext->stateFlags;
+OSDefineMetaClassAndStructors( IOPMRequest, IOCommand );
 
-    theContext->us->messageClient(theContext->msgType,object, &notify);
+IOPMRequest * IOPMRequest::create( void )
+{
+       IOPMRequest * me = OSTypeAlloc(IOPMRequest);
+       if (me && !me->init(0, kIOPMRequestTypeInvalid))
+       {
+               me->release();
+               me = 0;
+       }
+       return me;
 }
 
-
-// **********************************************************************************
-// checkForDone
-//
-// **********************************************************************************
-bool IOService::checkForDone ( void )
+bool IOPMRequest::init( IOService * target, IOOptionBits type )
 {
-    int i = 0;
-    OSObject * theFlag;
+       if (!IOCommand::init())
+               return false;
 
-    IOLockLock(priv->flags_lock);
-    if ( pm_vars->responseFlags == NULL ) {
-        IOLockUnlock(priv->flags_lock);
-        return true;
-    }
-    for ( i = 0; ; i++ ) {
-        theFlag = pm_vars->responseFlags->getObject(i);
-        if ( theFlag == NULL ) {
-            break;
-        }
-        if ( ((OSBoolean *)theFlag)->isFalse() ) {
-            IOLockUnlock(priv->flags_lock);
-            return false;
-        }
-    }
-    IOLockUnlock(priv->flags_lock);
-    return true;
-}
+       fType             = type;
+       fTarget           = target;
+    fCompletionStatus = kIOReturnSuccess;
 
+       if (fTarget)
+               fTarget->retain();
 
-// **********************************************************************************
-// responseValid
-//
-// **********************************************************************************
-bool IOService::responseValid ( unsigned long x )
-{
-    UInt16 serialComponent;
-    UInt16 ordinalComponent;
-    OSObject * theFlag;
-    unsigned long refcon = (unsigned long)x;
-    OSBoolean * aBool;
-    
-    serialComponent = (refcon>>16) & 0xFFFF;
-    ordinalComponent = refcon & 0xFFFF;
-    
-    if ( serialComponent != pm_vars->serialNumber ) {
-        return false;
-    }
-    
-    IOLockLock(priv->flags_lock);
-    if ( pm_vars->responseFlags == NULL ) {
-        IOLockUnlock(priv->flags_lock);
-        return false;
-    }
-    
-    theFlag = pm_vars->responseFlags->getObject(ordinalComponent);
-    
-    if ( theFlag == 0 ) {
-        IOLockUnlock(priv->flags_lock);
-        return false;
-    }
-    
-    if ( ((OSBoolean *)theFlag)->isFalse() ) {
-        aBool = OSBoolean::withBoolean(true);
-        pm_vars->responseFlags->replaceObject(ordinalComponent,aBool);
-        aBool->release();
-    }
-    
-    IOLockUnlock(priv->flags_lock);
-    return true;
+       return true;
 }
 
-
-// **********************************************************************************
-// allowPowerChange
-//
-// Our power state is about to lower, and we have notified applications
-// and kernel clients, and one of them has acknowledged.  If this is the last to do
-// so, and all acknowledgements are positive, we continue with the power change.
-//
-// We serialize this processing with timer expiration with a command gate on the
-// power management workloop, which the timer expiration is command gated to as well.
-// **********************************************************************************
-IOReturn IOService::allowPowerChange ( unsigned long refcon )
+void IOPMRequest::reset( void )
 {
-    if ( ! initialized ) {
-        return kIOReturnSuccess;                               // we're unloading
-    }
+       assert( fWorkWaitCount == 0 );
+       assert( fFreeWaitCount == 0 );
 
-    return pm_vars->PMcommandGate->runAction(serializedAllowPowerChange,(void *)refcon);
-}
-    
-    
-IOReturn serializedAllowPowerChange ( OSObject *owner, void * refcon, void *, void *, void *)
-{
-    return ((IOService *)owner)->serializedAllowPowerChange2((unsigned long)refcon);
-}
+       detachNextRequest();
+    detachRootRequest();
 
-IOReturn IOService::serializedAllowPowerChange2 ( unsigned long refcon )
-{
-    if ( ! responseValid(refcon) ) {                                                   // response valid?
-        pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogAcknowledgeErr5,refcon,0);
-        return kIOReturnSuccess;                                                       // no, just return
+       fType = kIOPMRequestTypeInvalid;
+
+       if (fCompletionAction)
+       {
+        fCompletionAction(fCompletionTarget, fCompletionParam, fCompletionStatus);
     }
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogClientAcknowledge,refcon,0);
 
-    return allowCancelCommon();
+       if (fTarget)
+       {
+               fTarget->release();
+               fTarget = 0;
+       }       
 }
 
-
-// **********************************************************************************
-// cancelPowerChange
-//
-// Our power state is about to lower, and we have notified applications
-// and kernel clients, and one of them has vetoed the change.  If this is the last
-// client to respond, we abandon the power change.
-//
-// We serialize this processing with timer expiration with a command gate on the
-// power management workloop, which the timer expiration is command gated to as well.
-// **********************************************************************************
-IOReturn IOService::cancelPowerChange ( unsigned long refcon )
+bool IOPMRequest::attachNextRequest( IOPMRequest * next )
 {
-    if ( ! initialized ) {
-        return kIOReturnSuccess;                               // we're unloading
-    }
+    bool ok = false;
 
-    return pm_vars->PMcommandGate->runAction(serializedCancelPowerChange,(void *)refcon);
+    if (!fRequestNext)
+    {
+        // Postpone the execution of the next request after
+        // this request.
+        fRequestNext = next;
+        fRequestNext->fWorkWaitCount++;
+#if LOG_REQUEST_ATTACH
+        kprintf("Attached next: %p [0x%x] -> %p [0x%x, %u] %s\n",
+            this, (uint32_t) fType, fRequestNext,
+            (uint32_t) fRequestNext->fType,
+            (uint32_t) fRequestNext->fWorkWaitCount,
+            fTarget->getName());
+#endif
+        ok = true;
+    }
+    return ok;
 }
-    
-    
-IOReturn serializedCancelPowerChange ( OSObject *owner, void * refcon, void *, void *, void *)
+
+bool IOPMRequest::detachNextRequest( void )
 {
-    return ((IOService *)owner)->serializedCancelPowerChange2((unsigned long)refcon);
+    bool ok = false;
+
+    if (fRequestNext)
+    {
+        assert(fRequestNext->fWorkWaitCount);
+        if (fRequestNext->fWorkWaitCount)
+            fRequestNext->fWorkWaitCount--;
+#if LOG_REQUEST_ATTACH
+        kprintf("Detached next: %p [0x%x] -> %p [0x%x, %u] %s\n",
+            this, (uint32_t) fType, fRequestNext,
+            (uint32_t) fRequestNext->fType,
+            (uint32_t) fRequestNext->fWorkWaitCount,
+            fTarget->getName());
+#endif
+        fRequestNext = 0;
+        ok = true;
+    }
+    return ok;
 }
 
-IOReturn IOService::serializedCancelPowerChange2 ( unsigned long refcon )
+bool IOPMRequest::attachRootRequest( IOPMRequest * root )
 {
-    if ( ! responseValid(refcon) ) {                                                   // response valid?
-        pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogAcknowledgeErr5,refcon,0);
-        return kIOReturnSuccess;                                                       // no, just return
-    }
-    pm_vars->thePlatform->PMLog(pm_vars->ourName,PMlogClientCancel,refcon,0);
-    
-    pm_vars->doNotPowerDown = true;
+    bool ok = false;
 
-    return allowCancelCommon();
+    if (!fRequestRoot)
+    {
+        // Delay the completion of the root request after
+        // this request.
+        fRequestRoot = root;
+        fRequestRoot->fFreeWaitCount++;
+#if LOG_REQUEST_ATTACH
+        kprintf("Attached root: %p [0x%x] -> %p [0x%x, %u] %s\n",
+            this, (uint32_t) fType, fRequestRoot,
+            (uint32_t) fRequestRoot->fType,
+            (uint32_t) fRequestRoot->fFreeWaitCount,
+            fTarget->getName());
+#endif
+        ok = true;
+    }
+    return ok;
 }
 
-
-// **********************************************************************************
-// allowCancelCommon
-//
-// **********************************************************************************
-IOReturn IOService::allowCancelCommon ( void )
+bool IOPMRequest::detachRootRequest( void )
 {
-    if (! acquire_lock() ) {
-        return kIOReturnSuccess;
-    }
-
-    if ( checkForDone() ) {                                     // is this the last response?
-        stop_ack_timer();                                       // yes, stop the timer
-        IOUnlock(priv->our_lock);
-        IOLockLock(priv->flags_lock);
-        if ( pm_vars->responseFlags ) {
-            pm_vars->responseFlags->release();
-            pm_vars->responseFlags = NULL;
-        }
-        IOLockUnlock(priv->flags_lock);
-        switch (priv->machine_state) {
-            case IOPMour_prechange_03:                         // our change, was it vetoed?
-                if ( ! pm_vars->doNotPowerDown ) {
-                    our_prechange_03();                         // no, we can continue
-                }
-                else {
-                    tellNoChangeDown(priv->head_note_state);   // yes, rescind the warning
-                    priv->head_note_flags |= IOPMNotDone;      // mark the change note un-actioned
-                    all_done();                                        // and we're done
-                }
-                break;
-            case IOPMour_prechange_04:
-                our_prechange_04();  
-                break;
-            case IOPMour_prechange_05:
-                our_prechange_05();                             // our change, continue
-                break;
-            case IOPMparent_down_0:
-                parent_down_04();                               // parent change, continue
-                break;
-            case IOPMparent_down_05:
-                parent_down_05();                               // parent change, continue
-                break;
-        }
-    }
+    bool ok = false;
 
-    IOUnlock(priv->our_lock);                                  // not done yet
-    return kIOReturnSuccess;
+    if (fRequestRoot)
+    {
+        assert(fRequestRoot->fFreeWaitCount);
+        if (fRequestRoot->fFreeWaitCount)
+            fRequestRoot->fFreeWaitCount--;
+#if LOG_REQUEST_ATTACH
+        kprintf("Detached root: %p [0x%x] -> %p [0x%x, %u] %s\n",
+            this, (uint32_t) fType, fRequestRoot,
+            (uint32_t) fRequestRoot->fType,
+            (uint32_t) fRequestRoot->fFreeWaitCount,
+            fTarget->getName());
+#endif
+        fRequestRoot = 0;
+        ok = true;
+    }
+    return ok;
 }
 
+// MARK: -
+// MARK: IOPMRequestQueue
 
 //*********************************************************************************
-// clampPowerOn
+// IOPMRequestQueue Class
 //
-// Set to highest available power state for a minimum of duration milliseconds
+// Global queues. Queues are created once and never released.
 //*********************************************************************************
 
-#define kFiveMinutesInNanoSeconds (300 * NSEC_PER_SEC)
+OSDefineMetaClassAndStructors( IOPMRequestQueue, IOEventSource );
 
-void IOService::clampPowerOn (unsigned long duration)
+IOPMRequestQueue * IOPMRequestQueue::create( IOService * inOwner, Action inAction )
 {
-  changePowerStateToPriv (pm_vars->theNumberOfPowerStates-1);
-
-  if (  priv->clampTimerEventSrc == NULL ) {
-    priv->clampTimerEventSrc = IOTimerEventSource::timerEventSource(this,
-                                                    c_PM_Clamp_Timer_Expired);
-
-    IOWorkLoop * workLoop = getPMworkloop ();
-
-    if ( !priv->clampTimerEventSrc || !workLoop ||
-       ( workLoop->addEventSource(  priv->clampTimerEventSrc) != kIOReturnSuccess) ) {
+       IOPMRequestQueue * me = OSTypeAlloc(IOPMRequestQueue);
+       if (me && !me->init(inOwner, inAction))
+       {
+               me->release();
+               me = 0;
+       }
+       return me;
+}
 
-    }
-  }
+bool IOPMRequestQueue::init( IOService * inOwner, Action inAction )
+{
+       if (!inAction || !IOEventSource::init(inOwner, (IOEventSourceAction)inAction))
+        return false;
 
-    priv->clampTimerEventSrc->setTimeout(kFiveMinutesInNanoSeconds, NSEC_PER_SEC);
+       queue_init(&fQueue);
+       fLock = IOLockAlloc();
+       return (fLock != 0);
 }
 
-//*********************************************************************************
-// PM_Clamp_Timer_Expired
-//
-// called when clamp timer expires...set power state to 0.
-//*********************************************************************************
-
-void IOService::PM_Clamp_Timer_Expired (void)
+void IOPMRequestQueue::free( void )
 {
-    if ( ! initialized ) {
-        return;                                        // we're unloading
-    }
+       if (fLock)
+       {
+               IOLockFree(fLock);
+               fLock = 0;
+       }
+       return IOEventSource::free();
+}
 
-  changePowerStateToPriv (0);
+void IOPMRequestQueue::queuePMRequest( IOPMRequest * request )
+{
+       assert(request);
+       IOLockLock(fLock);
+       queue_enter(&fQueue, request, IOPMRequest *, fCommandChain);
+       IOLockUnlock(fLock);
+       if (workLoop) signalWorkAvailable();
 }
 
-//*********************************************************************************
-// c_PM_clamp_Timer_Expired (C Func)
-//
-// Called when our clamp timer expires...we will call the object method.
-//*********************************************************************************
+void
+IOPMRequestQueue::queuePMRequestChain( IOPMRequest ** requests, IOItemCount count )
+{
+       IOPMRequest * next;
+
+       assert(requests && count);
+       IOLockLock(fLock);
+       while (count--)
+       {
+               next = *requests;
+               requests++;
+               queue_enter(&fQueue, next, IOPMRequest *, fCommandChain);
+       }
+       IOLockUnlock(fLock);
+       if (workLoop) signalWorkAvailable();
+}
 
-void c_PM_Clamp_Timer_Expired (OSObject * client, IOTimerEventSource *)
+bool IOPMRequestQueue::checkForWork( void )
 {
-  if (client)
-    ((IOService *)client)->PM_Clamp_Timer_Expired ();
+    Action                     dqAction = (Action) action;
+       IOPMRequest *   request;
+       IOService *             target;
+       bool                    more = false;
+
+       IOLockLock( fLock );
+
+       while (!queue_empty(&fQueue))
+       {
+               queue_remove_first( &fQueue, request, IOPMRequest *, fCommandChain );           
+               IOLockUnlock( fLock );
+               target = request->getTarget();
+               assert(target);
+               more |= (*dqAction)( target, request, this );
+               IOLockLock( fLock );
+       }
+
+       IOLockUnlock( fLock );
+       return more;
 }
 
+// MARK: -
+// MARK: IOPMWorkQueue
 
 //*********************************************************************************
-// setPowerState
+// IOPMWorkQueue Class
 //
-// Does nothing here.  This should be implemented in a subclass driver.
+// Queue of IOServicePM objects with busy IOPMRequest(s).
 //*********************************************************************************
 
-IOReturn IOService::setPowerState ( unsigned long powerStateOrdinal, IOService* whatDevice )
+OSDefineMetaClassAndStructors( IOPMWorkQueue, IOEventSource );
+
+IOPMWorkQueue *
+IOPMWorkQueue::create( IOService * inOwner, Action work, Action retire )
 {
-    return IOPMNoErr;
+       IOPMWorkQueue * me = OSTypeAlloc(IOPMWorkQueue);
+       if (me && !me->init(inOwner, work, retire))
+       {
+               me->release();
+               me = 0;
+       }
+       return me;
 }
 
+bool IOPMWorkQueue::init( IOService * inOwner, Action work, Action retire )
+{
+       if (!work || !retire ||
+               !IOEventSource::init(inOwner, (IOEventSourceAction)0))
+               return false;
 
-//*********************************************************************************
-// maxCapabilityForDomainState
-//
-// Finds the highest power state in the array whose input power
-// requirement is equal to the input parameter.  Where a more intelligent
-// decision is possible, override this in the subclassed driver.
-//*********************************************************************************
+       queue_init(&fWorkQueue);
 
-unsigned long IOService::maxCapabilityForDomainState ( IOPMPowerFlags domainState )
-{
-   int i;
+       fWorkAction    = work;
+       fRetireAction  = retire;
+    fConsumerCount = fProducerCount = 0;
 
-   if (pm_vars->theNumberOfPowerStates == 0 ) {
-       return 0;
-   }
-   for ( i = (pm_vars->theNumberOfPowerStates)-1; i >= 0; i-- ) {
-       if (  (domainState & pm_vars->thePowerStates[i].inputPowerRequirement) == pm_vars->thePowerStates[i].inputPowerRequirement ) {
-           return i;
-       }
-   }
-   return 0;
+       return true;
 }
 
+bool IOPMWorkQueue::queuePMRequest( IOPMRequest * request, IOServicePM * pwrMgt )
+{
+    bool more = false;
+    bool empty;
 
-//*********************************************************************************
-// initialPowerStateForDomainState
-//
-// Finds the highest power state in the array whose input power
-// requirement is equal to the input parameter.  Where a more intelligent
-// decision is possible, override this in the subclassed driver.
-//*********************************************************************************
+       assert( request );
+    assert( pwrMgt );
+       assert( onThread() );
+    assert( queue_next(&request->fCommandChain) ==
+            queue_prev(&request->fCommandChain) );
 
-unsigned long IOService::initialPowerStateForDomainState ( IOPMPowerFlags domainState )
-{
-  int i;
+       gIOPMBusyCount++;
 
-   if (pm_vars->theNumberOfPowerStates == 0 ) {
-      return 0;
-  }
-   for ( i = (pm_vars->theNumberOfPowerStates)-1; i >= 0; i-- ) {
-       if (  (domainState & pm_vars->thePowerStates[i].inputPowerRequirement) == pm_vars->thePowerStates[i].inputPowerRequirement ) {
-          return i;
-      }
-  }
-  return 0;
-}
+    // Add new request to the tail of the per-service request queue.
+    // Then immediately check the request queue to minimize latency
+    // if the queue was empty.
 
+    empty = queue_empty(&pwrMgt->RequestHead);
+       queue_enter(&pwrMgt->RequestHead, request, IOPMRequest *, fCommandChain);
+    if (empty)
+    {
+        more = checkRequestQueue(&pwrMgt->RequestHead, &empty);
+        if (!empty)
+        {
+            // New Request is blocked, add IOServicePM to work queue.
+            assert( queue_next(&pwrMgt->WorkChain) ==
+                    queue_prev(&pwrMgt->WorkChain) );
+
+            queue_enter(&fWorkQueue, pwrMgt, IOServicePM *, WorkChain);
+            fQueueLength++;
+            PM_LOG3("IOPMWorkQueue: [%u] added %s@%p to queue\n",
+                fQueueLength, pwrMgt->Name, pwrMgt);
+        }
+    }
 
-//*********************************************************************************
-// powerStateForDomainState
-//
-// Finds the highest power state in the array whose input power
-// requirement is equal to the input parameter.  Where a more intelligent
-// decision is possible, override this in the subclassed driver.
-//*********************************************************************************
+    return more;
+}
 
-unsigned long IOService::powerStateForDomainState ( IOPMPowerFlags domainState )
+bool IOPMWorkQueue::checkRequestQueue( queue_head_t * queue, bool * empty )
 {
-  int i;
+       IOPMRequest *   request;
+       IOService *             target;
+    bool            more = false;
+       bool                    done = false;
+
+    assert(!queue_empty(queue));
+    do {
+               request = (IOPMRequest *) queue_first(queue);
+               if (request->isWorkBlocked())
+            break;  // cannot start, blocked on attached request
+
+               target = request->getTarget();
+        done = (*fWorkAction)( target, request, this );
+               if (!done)
+            break;  // work started, blocked on PM state machine
+
+        assert(gIOPMBusyCount > 0);
+               if (gIOPMBusyCount)
+            gIOPMBusyCount--;
+
+        queue_remove_first(queue, request, IOPMRequest *, fCommandChain);
+        more |= (*fRetireAction)( target, request, this );
+        done = queue_empty(queue);
+    } while (!done);
+
+    *empty = done;
+
+    if (more)
+    {
+        // Retired request blocks another request, since the
+        // blocked request may reside in the work queue, we
+        // must bump the producer count to avoid work stall.
+        fProducerCount++;
+    }
 
-   if (pm_vars->theNumberOfPowerStates == 0 ) {
-      return 0;
-  }
-   for ( i = (pm_vars->theNumberOfPowerStates)-1; i >= 0; i-- ) {
-       if (  (domainState & pm_vars->thePowerStates[i].inputPowerRequirement) == pm_vars->thePowerStates[i].inputPowerRequirement ) {
-          return i;
-      }
-  }
-  return 0;
+    return more;
 }
 
+bool IOPMWorkQueue::checkForWork( void )
+{
+       IOServicePM *   entry;
+       IOServicePM *   next;
+    bool                       more = false;
+    bool            empty;
 
-//*********************************************************************************
-// didYouWakeSystem
-//
-// Does nothing here.  This should be implemented in a subclass driver.
-//*********************************************************************************
+#if WORK_QUEUE_STATS
+    fStatCheckForWork++;
+#endif
 
-bool IOService::didYouWakeSystem  ( void )
-{
-    return false;
-}
+    // Each producer signal triggers a full iteration over
+    // all IOServicePM entries in the work queue.
 
+    while (fConsumerCount != fProducerCount)
+    {
+        PM_LOG3("IOPMWorkQueue: checkForWork %u %u\n",
+            fProducerCount, fConsumerCount);
 
-//*********************************************************************************
-// powerStateWillChangeTo
-//
-// Does nothing here.  This should be implemented in a subclass driver.
-//*********************************************************************************
+        fConsumerCount = fProducerCount;
 
-IOReturn IOService::powerStateWillChangeTo ( IOPMPowerFlags, unsigned long, IOService*)
-{
-    return 0;
-}
+#if WORK_QUEUE_STATS        
+        if (queue_empty(&fWorkQueue))
+        {
+            fStatQueueEmpty++;
+            break;
+        }
+        fStatScanEntries++;
+        uint32_t cachedWorkCount = gIOPMWorkCount;
+#endif
+
+        entry = (IOServicePM *) queue_first(&fWorkQueue);
+        while (!queue_end(&fWorkQueue, (queue_entry_t) entry))
+        {
+            more |= checkRequestQueue(&entry->RequestHead, &empty);
+
+            // Get next entry, points to head if current entry is last.
+            next = (IOServicePM *) queue_next(&entry->WorkChain);
+
+            // if request queue is empty, remove IOServicePM from queue.
+            if (empty)
+            {
+                assert(fQueueLength);
+                if (fQueueLength) fQueueLength--;
+                PM_LOG3("IOPMWorkQueue: [%u] removed %s@%p from queue\n",
+                    fQueueLength, entry->Name, entry);
+                queue_remove(&fWorkQueue, entry, IOServicePM *, WorkChain);
+            }
+            entry = next;
+        }
 
+#if WORK_QUEUE_STATS
+        if (cachedWorkCount == gIOPMWorkCount)
+            fStatNoWorkDone++;
+#endif
+    }
 
-//*********************************************************************************
-// powerStateDidChangeTo
-//
-// Does nothing here.  This should be implemented in a subclass driver.
-//*********************************************************************************
+    return more;
+}
 
-IOReturn IOService::powerStateDidChangeTo ( IOPMPowerFlags, unsigned long, IOService*)
+void IOPMWorkQueue::signalWorkAvailable( void )
 {
-    return 0;
+    fProducerCount++;
+       IOEventSource::signalWorkAvailable();
 }
 
-
-//*********************************************************************************
-// powerChangeDone
-//
-// Does nothing here.  This should be implemented in a subclass policy-maker.
-//*********************************************************************************
-
-void IOService::powerChangeDone ( unsigned long )
+void IOPMWorkQueue::incrementProducerCount( void )
 {
+    fProducerCount++;
 }
 
+// MARK: -
+// MARK: IOPMCompletionQueue
 
 //*********************************************************************************
-// newTemperature
-//
-// Does nothing here.  This should be implemented in a subclass driver.
+// IOPMCompletionQueue Class
 //*********************************************************************************
 
-IOReturn IOService::newTemperature ( long currentTemp, IOService * whichZone )
+OSDefineMetaClassAndStructors( IOPMCompletionQueue, IOEventSource );
 
+IOPMCompletionQueue *
+IOPMCompletionQueue::create( IOService * inOwner, Action inAction )
 {
-    return IOPMNoErr;
+       IOPMCompletionQueue * me = OSTypeAlloc(IOPMCompletionQueue);
+       if (me && !me->init(inOwner, inAction))
+       {
+               me->release();
+               me = 0;
+       }
+       return me;
 }
 
+bool IOPMCompletionQueue::init( IOService * inOwner, Action inAction )
+{
+       if (!inAction || !IOEventSource::init(inOwner, (IOEventSourceAction)inAction))
+        return false;
 
-#undef super
-#define super OSObject
+       queue_init(&fQueue);
+       return true;
+}
 
-OSDefineMetaClassAndStructors(IOPMprot, OSObject)
-//*********************************************************************************
-// serialize
-//
-// Serialize protected instance variables for debug output.
-//*********************************************************************************
-bool IOPMprot::serialize(OSSerialize *s) const
+bool IOPMCompletionQueue::queuePMRequest( IOPMRequest * request )
 {
-    OSString * theOSString;
-    char * buffer;
-    char * ptr;
-    int i;
-    bool       rtn_code;
+    bool more;
 
-    buffer = ptr = IONew(char, 2000);
-    if(!buffer)
-        return false;
+       assert(request);
+    // unblock dependent request
+    more = request->detachNextRequest();
+       queue_enter(&fQueue, request, IOPMRequest *, fCommandChain);
+    return more;
+}
 
-    ptr += sprintf(ptr,"{ theNumberOfPowerStates = %d, ",(unsigned int)theNumberOfPowerStates);
-
-    if ( theNumberOfPowerStates != 0 ) {
-        ptr += sprintf(ptr,"version %d, ",(unsigned int)thePowerStates[0].version);
-    }
-
-    if ( theNumberOfPowerStates != 0 ) {
-        for ( i = 0; i < (int)theNumberOfPowerStates; i++ ) {
-            ptr += sprintf(ptr,"power state %d = { ",i);
-            ptr += sprintf(ptr,"capabilityFlags %08x, ",(unsigned int)thePowerStates[i].capabilityFlags);
-            ptr += sprintf(ptr,"outputPowerCharacter %08x, ",(unsigned int)thePowerStates[i].outputPowerCharacter);
-            ptr += sprintf(ptr,"inputPowerRequirement %08x, ",(unsigned int)thePowerStates[i].inputPowerRequirement);
-            ptr += sprintf(ptr,"staticPower %d, ",(unsigned int)thePowerStates[i].staticPower);
-            ptr += sprintf(ptr,"unbudgetedPower %d, ",(unsigned int)thePowerStates[i].unbudgetedPower);
-            ptr += sprintf(ptr,"powerToAttain %d, ",(unsigned int)thePowerStates[i].powerToAttain);
-            ptr += sprintf(ptr,"timeToAttain %d, ",(unsigned int)thePowerStates[i].timeToAttain);
-            ptr += sprintf(ptr,"settleUpTime %d, ",(unsigned int)thePowerStates[i].settleUpTime);
-            ptr += sprintf(ptr,"timeToLower %d, ",(unsigned int)thePowerStates[i].timeToLower);
-            ptr += sprintf(ptr,"settleDownTime %d, ",(unsigned int)thePowerStates[i].settleDownTime);
-            ptr += sprintf(ptr,"powerDomainBudget %d }, ",(unsigned int)thePowerStates[i].powerDomainBudget);
+bool IOPMCompletionQueue::checkForWork( void )
+{
+    Action                     dqAction = (Action) action;
+       IOPMRequest *   request;
+       IOPMRequest *   next;
+       IOService *             target;
+       bool                    more = false;
+
+    request = (IOPMRequest *) queue_first(&fQueue);
+    while (!queue_end(&fQueue, (queue_entry_t) request))
+    {
+        next = (IOPMRequest *) queue_next(&request->fCommandChain);
+               if (!request->isFreeBlocked())
+        {
+            queue_remove(&fQueue, request, IOPMRequest *, fCommandChain);
+            target = request->getTarget();
+            assert(target);
+            more |= (*dqAction)( target, request, this );
         }
+        request = next;
     }
 
-    ptr += sprintf(ptr,"aggressiveness = %d, ",(unsigned int)aggressiveness);
-    ptr += sprintf(ptr,"myCurrentState = %d, ",(unsigned int)myCurrentState);
-    ptr += sprintf(ptr,"parentsCurrentPowerFlags = %08x, ",(unsigned int)parentsCurrentPowerFlags);
-    ptr += sprintf(ptr,"maxCapability = %d }",(unsigned int)maxCapability);
-
-    theOSString = OSString::withCString(buffer);
-    rtn_code = theOSString->serialize(s);
-    theOSString->release();
-    IODelete(buffer, char, 2000);
-
-    return rtn_code;
+    return more;
 }
 
+// MARK: -
+// MARK: IOServicePM
 
-#undef super
-#define super OSObject
+OSDefineMetaClassAndStructors(IOServicePM, OSObject)
 
-OSDefineMetaClassAndStructors(IOPMpriv, OSObject)
 //*********************************************************************************
 // serialize
 //
-// Serialize private instance variables for debug output.
+// Serialize IOServicePM for debugging.
 //*********************************************************************************
-bool IOPMpriv::serialize(OSSerialize *s) const
+
+static void
+setPMProperty( OSDictionary * dict, const char * key, uint64_t value )
 {
-    OSString *                 theOSString;
-    bool                       rtn_code;
-    char *                     buffer;
-    char *                     ptr;
-    IOPMinformee *             nextObject;
+    OSNumber * num = OSNumber::withNumber(value, sizeof(value) * 8);
+    if (num)
+    {
+        dict->setObject(key, num);
+        num->release();
+    }
+}
 
-    buffer = ptr = IONew(char, 2000);
-    if(!buffer)
-        return false;
+IOReturn IOServicePM::gatedSerialize( OSSerialize * s  )
+{
+       OSDictionary *  dict;
+       bool                    ok = false;
+       int                             dictSize = 5;
 
-    ptr += sprintf(ptr,"{ this object = %08x",(unsigned int)owner);
-    if ( we_are_root ) {
-        ptr += sprintf(ptr," (root)");
-    }
-    ptr += sprintf(ptr,", ");
+       if (IdleTimerPeriod)
+               dictSize += 4;
 
-    nextObject = interestedDrivers->firstInList();                     // display interested drivers
-    while (  nextObject != NULL ) {
-        ptr += sprintf(ptr,"interested driver = %08x, ",(unsigned int)nextObject->whatObject);
-        nextObject  =  interestedDrivers->nextInList(nextObject);
-    }
+#if WORK_QUEUE_STATS
+    if (gIOPMRootNode == ControllingDriver)
+        dictSize += 4;
+#endif
 
-    if ( machine_state != IOPMfinished ) {
-        ptr += sprintf(ptr,"machine_state = %d, ",(unsigned int)machine_state);
-        ptr += sprintf(ptr,"driver_timer = %d, ",(unsigned int)driver_timer);
-        ptr += sprintf(ptr,"settle_time = %d, ",(unsigned int)settle_time);
-        ptr += sprintf(ptr,"head_note_flags = %08x, ",(unsigned int)head_note_flags);
-        ptr += sprintf(ptr,"head_note_state = %d, ",(unsigned int)head_note_state);
-        ptr += sprintf(ptr,"head_note_outputFlags = %08x, ",(unsigned int)head_note_outputFlags);
-        ptr += sprintf(ptr,"head_note_domainState = %08x, ",(unsigned int)head_note_domainState);
-        ptr += sprintf(ptr,"head_note_capabilityFlags = %08x, ",(unsigned int)head_note_capabilityFlags);
-        ptr += sprintf(ptr,"head_note_pendingAcks = %d, ",(unsigned int)head_note_pendingAcks);
-    }
+    if (PowerClients)
+        dict = OSDictionary::withDictionary(
+            PowerClients, PowerClients->getCount() + dictSize);
+    else
+        dict = OSDictionary::withCapacity(dictSize);
+
+       if (dict)
+       {
+        setPMProperty(dict, "CurrentPowerState", CurrentPowerState);
+        if (NumberOfPowerStates)
+            setPMProperty(dict, "MaxPowerState", NumberOfPowerStates-1);
+        if (DesiredPowerState != CurrentPowerState)
+            setPMProperty(dict, "DesiredPowerState", DesiredPowerState);
+        if (kIOPM_Finished != MachineState)
+            setPMProperty(dict, "MachineState", MachineState);
+        if (DeviceOverrideEnabled)
+            dict->setObject("PowerOverrideOn", kOSBooleanTrue);
+
+               if (IdleTimerPeriod)
+               {
+            AbsoluteTime    now;
+            AbsoluteTime    delta;
+            uint64_t        nsecs;
+
+            clock_get_uptime(&now);
+
+                       // The idle timer period in milliseconds.
+                       setPMProperty(dict, "IdleTimerPeriod", IdleTimerPeriod * 1000ULL);
+
+            // The number of activity tickles recorded since device idle
+            setPMProperty(dict, "ActivityTickles", ActivityTickleCount);
+
+            if (AbsoluteTime_to_scalar(&DeviceActiveTimestamp))
+            {
+                // The number of milliseconds since the last activity tickle.
+                delta = now;
+                SUB_ABSOLUTETIME(&delta, &DeviceActiveTimestamp);
+                absolutetime_to_nanoseconds(delta, &nsecs);
+                setPMProperty(dict, "TimeSinceLastTickle", NS_TO_MS(nsecs));
+            }
 
-    if ( device_overrides ) {
-        ptr += sprintf(ptr,"device overrides, ");
-    }
-    ptr += sprintf(ptr,"driverDesire = %d, ",(unsigned int)driverDesire);
-    ptr += sprintf(ptr,"deviceDesire = %d, ",(unsigned int)deviceDesire);
-    ptr += sprintf(ptr,"ourDesiredPowerState = %d, ",(unsigned int)ourDesiredPowerState);
-    ptr += sprintf(ptr,"previousRequest = %d }",(unsigned int)previousRequest);
+            if (AbsoluteTime_to_scalar(&IdleTimerStartTime))
+            {
+                // The number of milliseconds since the last device idle.
+                delta = now;
+                SUB_ABSOLUTETIME(&delta, &IdleTimerStartTime);
+                absolutetime_to_nanoseconds(delta, &nsecs);
+                setPMProperty(dict, "TimeSinceDeviceIdle", NS_TO_MS(nsecs));
+            }
+               }
+
+#if WORK_QUEUE_STATS
+        if (gIOPMRootNode == Owner)
+        {
+            setPMProperty(dict, "WQ-CheckForWork",
+                gIOPMWorkQueue->fStatCheckForWork);
+            setPMProperty(dict, "WQ-ScanEntries",
+                gIOPMWorkQueue->fStatScanEntries);
+            setPMProperty(dict, "WQ-QueueEmpty",
+                gIOPMWorkQueue->fStatQueueEmpty);
+            setPMProperty(dict, "WQ-NoWorkDone",
+                gIOPMWorkQueue->fStatNoWorkDone);
+        }
+#endif
+
+               ok = dict->serialize(s);
+               dict->release();
+       }
+
+       return (ok ? kIOReturnSuccess : kIOReturnNoMemory);
+}
+
+bool IOServicePM::serialize( OSSerialize * s ) const
+{
+    IOReturn ret = kIOReturnNotReady;
 
-    theOSString =  OSString::withCString(buffer);
-    rtn_code = theOSString->serialize(s);
-    theOSString->release();
-    IODelete(buffer, char, 2000);
+    if (gIOPMWorkLoop)
+       {
+               ret = gIOPMWorkLoop->runAction(
+            OSMemberFunctionCast(IOWorkLoop::Action, this, &IOServicePM::gatedSerialize),
+            (OSObject *) this, (void *) s);
+       }
+
+    return (kIOReturnSuccess == ret);
+}
+
+PMEventDetails* PMEventDetails::eventDetails(uint32_t   type,
+                                             const char *ownerName,
+                                             uintptr_t  ownerUnique,
+                                             const char *interestName,
+                                             uint8_t    oldState,
+                                             uint8_t    newState,
+                                             uint32_t   result,
+                                             uint32_t   elapsedTimeUS) {
+       
+       PMEventDetails *myself;
+       myself  = new PMEventDetails;
+       
+       if(myself) {
+               myself->eventType     = type;
+               myself->ownerName     = ownerName;
+               myself->ownerUnique   = ownerUnique;
+               myself->interestName  = interestName;
+               myself->oldState      = oldState;
+               myself->newState      = newState;
+               myself->result        = result;
+               myself->elapsedTimeUS = elapsedTimeUS;
+               
+               myself->eventClassifier = kIOPMEventClassDriverEvent;
+       }
+       
+       return myself;
+}
 
-    return rtn_code;
+
+PMEventDetails* PMEventDetails::eventDetails(uint32_t   type,
+                                             const char *uuid,
+                                             uint32_t   reason,
+                                             uint32_t   result) {
+       
+       PMEventDetails *myself;
+       myself  = new PMEventDetails;
+       
+       if(myself) {
+               myself->eventType     = type;
+               myself->uuid          = uuid;
+               myself->reason        = reason;
+               myself->result        = result;
+               
+               myself->eventClassifier = kIOPMEventClassSystemEvent;
+       }
+       
+       return myself;
 }