and51PowerManagerService深入分析三updatePowerStateLocked函数.docx
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and51PowerManagerService深入分析三updatePowerStateLocked函数
and5.1PowerManagerService深入分析（三）updatePowerStateLocked函数
PMS更新各个状态，最终都会调用updatePowerStateLocked函数，下面我们来分析下
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privatevoidupdatePowerStateLocked（）{
if（!
mSystemReady||mDirty==0）{//mDirty=0代表没有变化，或者系统没有准备好，直接退出
return;
}
if（!
Thread.holdsLock（mLock））{
Slog.wtf（TAG,"PowermanagerlockwasnotheldwhencallingupdatePowerStateLocked"）;
}
Trace.traceBegin（Trace.TRACE_TAG_POWER,"updatePowerState"）;
try{
//Phase0:
Basicstateupdates.
updateIsPoweredLocked（mDirty）;//更新电源状态
updateStayOnLocked（mDirty）;
updateScreenBrightnessBoostLocked（mDirty）;
updateIsPoweredLocked函数，先是要dirty有DIRTY_BATTERY_STATE标志位。
我们在下面分析下，什么时候会有这个标志位
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privatevoidupdateIsPoweredLocked（intdirty）{
if（（dirty&DIRTY_BATTERY_STATE）!
=0）{
finalbooleanwasPowered=mIsPowered;
finalintoldPlugType=mPlugType;
finalbooleanoldLevelLow=mBatteryLevelLow;
mIsPowered=mBatteryManagerInternal.isPowered（BatteryManager.BATTERY_PLUGGED_ANY）;//这些都是从BatteryService获取
mPlugType=mBatteryManagerInternal.getPlugType（）;
mBatteryLevel=mBatteryManagerInternal.getBatteryLevel（）;
mBatteryLevelLow=mBatteryManagerInternal.getBatteryLevelLow（）;
if（DEBUG_SPEW）{
Slog.d（TAG,"updateIsPoweredLocked:
wasPowered="+wasPowered
+",mIsPowered="+mIsPowered
+",oldPlugType="+oldPlugType
+",mPlugType="+mPlugType
+",mBatteryLevel="+mBatteryLevel）;
}
if（wasPowered!
=mIsPowered||oldPlugType!
=mPlugType）{//是否充电或者充电类型改变了
mDirty|=DIRTY_IS_POWERED;//mDirty置位
//Updatewirelessdockdetectionstate.
finalbooleandockedOnWirelessCharger=mWirelessChargerDetector.update（//无线充电相关
mIsPowered,mPlugType,mBatteryLevel）;
//Treatpluggingandunpluggingthedevicesasauseractivity.
//Usersfinditdisconcertingwhentheyplugorunplugthedevice
//anditshutsoffrightaway.
//Somedevicesalsowakethedevicewhenpluggedorunpluggedbecause
//theydon'thaveachargingLED.
finallongnow=SystemClock.uptimeMillis（）;
if（shouldWakeUpWhenPluggedOrUnpluggedLocked（wasPowered,oldPlugType,
dockedOnWirelessCharger））{//是否需要唤醒设备
wakeUpNoUpdateLocked（now,Process.SYSTEM_UID）;
}
userActivityNoUpdateLocked（//触发userActivity
now,PowerManager.USER_ACTIVITY_EVENT_OTHER,0,Process.SYSTEM_UID）;
//Tellthenotifierwhetherwirelesscharginghasstartedsothat
//itcanprovidefeedbacktotheuser.
if（dockedOnWirelessCharger）{//无线充电相关
mNotifier.onWirelessChargingStarted（）;
}
}
if（wasPowered!
=mIsPowered||oldLevelLow!
=mBatteryLevelLow）{
if（oldLevelLow!
=mBatteryLevelLow&&!
mBatteryLevelLow）{
if（DEBUG_SPEW）{
Slog.d（TAG,"updateIsPoweredLocked:
resettinglowpowersnooze"）;
}
mAutoLowPowerModeSnoozing=false;
}
updateLowPowerModeLocked（）;//更新低功耗模式
}
}
}
首先systemReady函数最终会把mDirty置位为DIRTY_BATTERY_STATE，还有收BatterySevice发出来的广播，最总也会置这个标志位。
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privatefinalclassBatteryReceiverextendsBroadcastReceiver{
@Override
publicvoidonReceive（Contextcontext,Intentintent）{
synchronized（mLock）{
handleBatteryStateChangedLocked（）;
}
}
}
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privatevoidhandleBatteryStateChangedLocked（）{
mDirty|=DIRTY_BATTERY_STATE;
updatePowerStateLocked（）;
}
再来看看电池状态发生什么变化要唤醒设备：
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privatebooleanshouldWakeUpWhenPluggedOrUnpluggedLocked（
booleanwasPowered,intoldPlugType,booleandockedOnWirelessCharger）{
//Don'twakewhenpoweredunlessconfiguredtodoso.
if（!
mWakeUpWhenPluggedOrUnpluggedConfig）{//如果资源中没有配置这项，直接退出不唤醒设备
returnfalse;
}
//Don'twakewhenundockedfromwirelesscharger.
//SeeWirelessChargerDetectorforjustification.
if（wasPowered&&!
mIsPowered
&&oldPlugType==BatteryManager.BATTERY_PLUGGED_WIRELESS）{//这是一个拔出的工作，然后之前的无线充电
returnfalse;
}
//Don'twakewhendockedonwirelesschargerunlesswearecertainofit.
//SeeWirelessChargerDetectorforjustification.
if（!
wasPowered&&mIsPowered
&&mPlugType==BatteryManager.BATTERY_PLUGGED_WIRELESS//插入动作，现在是无线充电
&&!
dockedOnWirelessCharger）{
returnfalse;
}
//Ifalreadydreamingandbecomingpowered,thendon'twake.
if（mIsPowered&&mWakefulness==WAKEFULNESS_DREAMING）{//正在充电，但是mWakefulness是做梦状态
returnfalse;
}
//Don'twakewhiletheatermodeisenabled.
if（mTheaterModeEnabled&&!
mWakeUpWhenPluggedOrUnpluggedInTheaterModeConfig）{
returnfalse;
}
//Otherwisewakeup!
returntrue;//其他就唤醒设备
}
继续分析updatePowerStateLocked函数，分析updateStayOnLocked函数。
一般这个函数mStatyon为fasle，除非在资源中设置哪种充电状态下可以长亮。
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privatevoidupdateStayOnLocked（intdirty）{
if（（dirty&（DIRTY_BATTERY_STATE|DIRTY_SETTINGS））!
=0）{//当dirty是电池状态和设置的状态改变时
finalbooleanwasStayOn=mStayOn;
if（mStayOnWhilePluggedInSetting!
=0//这个值从资源中读取，一般设置的话代表哪种充电时可以常亮
&&!
isMaximumScreenOffTimeoutFromDeviceAdminEnforcedLocked（））{//看有没有设mMaximumScreenOffTimeoutFromDeviceAdmin屏幕最大亮屏时间，没设默认最大。
那么这个函数返回是false
mStayOn=mBatteryManagerInternal.isPowered（mStayOnWhilePluggedInSetting）;
}else{
mStayOn=false;
}
if（mStayOn!
=wasStayOn）{
mDirty|=DIRTY_STAY_ON;
}
}
}
继续分析updatePowerStateLocked函数的updateScreenBrightnessBoostLocked函数，这个函数是更新屏幕是否保持最亮状态
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privatevoidupdateScreenBrightnessBoostLocked（intdirty）{
if（（dirty&DIRTY_SCREEN_BRIGHTNESS_BOOST）!
=0）{//这个状态实在boostScreenBrightnessInternal函数中设置最亮时置位，当然下面发送消息MSG_SCREEN_BRIGHTNESS_BOOST_TIMEOUT也会将这个标志位置位
if（mScreenBrightnessBoostInProgress）{//当前正在最亮屏幕这个状态
finallongnow=SystemClock.uptimeMillis（）;
mHandler.removeMessages（MSG_SCREEN_BRIGHTNESS_BOOST_TIMEOUT）;
if（mLastScreenBrightnessBoostTime>mLastSleepTime）{
finallongboostTimeout=mLastScreenBrightnessBoostTime+
SCREEN_BRIGHTNESS_BOOST_TIMEOUT;
if（boostTimeout>now）{//看当前时间是否小于最亮屏幕结束的时间
Messagemsg=mHandler.obtainMessage（MSG_SCREEN_BRIGHTNESS_BOOST_TIMEOUT）;
msg.setAsynchronous（true）;
mHandler.sendMessageAtTime（msg,boostTimeout）;//发送一个延迟的消息，到最亮屏幕结束的时候接受到消息，将标志位置为DIRTY_SCREEN_BRIGHTNESS_BOOST后，重新再回到这个函数
return;
}
}
mScreenBrightnessBoostInProgress=false;//回到这个函数时，直接将这个屏幕最亮状态的标志位改成false
userActivityNoUpdateLocked（now,//触发一个userActivity
PowerManager.USER_ACTIVITY_EVENT_OTHER,0,Process.SYSTEM_UID）;
}
}
}
下面看看MSG_SCREEN_BRIGHTNESS_BOOST_TIMEOUT消息的处理函数。
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caseMSG_SCREEN_BRIGHTNESS_BOOST_TIMEOUT:
handleScreenBrightnessBoostTimeout（）;
break;
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privatevoidhandleScreenBrightnessBoostTimeout（）{//runsonhandlerthread
synchronized（mLock）{
if（DEBUG_SPEW）{
Slog.d（TAG,"handleScreenBrightnessBoostTimeout"）;
}
mDirty|=DIRTY_SCREEN_BRIGHTNESS_BOOST;
updatePowerStateLocked（）;
}
}
接下来看updatePowerStateLocked函数的另一个阶段：
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//Phase1:
Updatewakefulness.
//Loopbecausethewakelockanduseractivitycomputationsareinfluenced
//bychangesinwakefulness.
finallongnow=SystemClock.uptimeMillis（）;
intdirtyPhase2=0;
for（;;）{
intdirtyPhase1=mDirty;//这个循环中每次新的mDirty全部给dirtyPhase1，并且在这个循环中使用这个dirty
dirtyPhase2|=dirtyPhase1;//dirtyPhase2会把之前所有的mDirty状态全部或上，然后用这个状态继续下面的函数
mDirty=0;//mDirty会在这里清零
updateWakeLockSummaryLocked（dirtyPhase1）;
updateUserActivitySummaryLocked（now,dirtyPhase1）;
if（!
updateWakefulnessLocked（dirtyPhase1））{
break;
}
}
先看下updateWakeLockSummaryLocked函数，更新wakelock的函数
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privatevoidupdateWakeLockSummaryLocked（intdirty）{
if（（dirty&（DIRTY_WAKE_LOCKS|DIRTY_WAKEFULNESS））!
=0）{
mWakeLockSummary=0;
finalintnumWakeLocks=mWakeLocks.size（）;
for（inti=0;ifinalWakeLockwakeLock=mWakeLocks.get（i）;
switch（wakeLock.mFlags&PowerManager.WAKE_LOCK_LEVEL_MASK）{//先根据wakelock的flag，mWakeLockSummary或上各种状态
casePowerManager.PARTIAL_WAKE_LOCK:
mWakeLockSummary|=WAKE_LOCK_CPU;
break;
casePowerManager.FULL_WAKE_LOCK:
mWakeLockSummary|=WAKE_LOCK_SCREEN_BRIGHT|WAKE_LOCK_BUTTON_BRIGHT;
break;
casePowerManager.SCREEN_BRIGHT_WAKE_LOCK:
mWakeLockSummary|=WAKE_LOCK_SCREEN_BRIGHT;
break;
casePowerManager.SCREEN_DIM_WAKE_LOCK:
mWakeLockSummary|=WAKE_LOCK_SCREEN_DIM;
break;
casePowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK:
//距离传感器相关
mWakeLockSummary|=WAKE_LOCK_PROXIMITY_SCREEN_OFF;
break;
casePowerManager.DOZE_WAKE_LOCK:
mWakeLockSummary|=WAKE_LOCK_DOZE;
break;
}
}
//Cancelwakelocksthatmakenosensebasedonthecurrentstate.
if（mWakefulness!
=WAKEFULNESS_DOZING）{//下面根据各种状态，将上面或上的mWakeLockSummary，有的减去
mWakeLockSummary&=~WAKE_LOCK_DOZE;
}
if（mWakefulness==WAKEFULNESS_ASLEEP
||（mWakeLockSummary&WAKE_LOCK_DOZE）!
=0）{
mWakeLockSummary&=~（WAKE_LOCK_SCREEN_BRIGHT|WAKE_LOCK_SCREEN_DIM
|WAKE_LOCK_BUTTON_BRIGHT）;
if（mWakefulness==WAKEFULNESS_ASLEEP）{
mWakeLockSummary&=~WAKE_LOCK_PROXIMITY_SCREEN_OFF;
}
}
//Inferimpliedwakelockswherenecessarybasedonthecurrentstate.
if（（mWakeLockSummary&（WAKE_LOCK_SCREEN_BRIGHT|WAKE_LOCK_SCREEN_DIM））!
=0）{//只要有屏幕锁，cpu锁必须持有
if（mWakefulness==WAKEFULNESS_AWAKE）{
mWakeLockSummary|=WAKE_LOCK_CPU|WAKE_LOCK_STAY_AWAKE;
}elseif（mWakefulness==WAKEFULNESS_DREAMING）{
mWakeLockSummary|=WAKE_LOCK_CPU;
}
}
if（DEBUG_SPEW）{
Slog.d（TAG,"updateWakeLockSummaryLocked:
mWakefulness="
+PowerManagerInternal.wakefulnessToString（mWakefulness）
+",mWakeLockSummary=0x"+Integer.toHexString（mWakeLockSummary））;
}
}
}
下面分析下updateUserActivitySummaryLocked函数
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privatevoidupdateUs
升级会员 