Android5.1 PowerManagerService深入分析
PowerManagerService提供Android系统的电源管理服务，主要功能是控制系统的待机状态，控制显示屏的开关和亮度调节等。
PowerManagerService在systemserver中创建，加入到serviceManager中：
mPowerManagerService = mSystemServiceManager.startService(PowerManagerService.class);
先从构造函数分析，代码如下：
public PowerManagerService(Context context) {
super(context);
mContext = context;
//创建处理消息的线程
mHandlerThread = new ServiceThread(TAG,
Process.THREAD_PRIORITY_DISPLAY, false /*allowIo*/);
mHandlerThread.start();
//创建Handler，注意mHandlerThread.getLooper()，每一个线程都只有一个looper，这样消息的处理会放在这个线程中
mHandler = new PowerManagerHandler(mHandlerThread.getLooper());
synchronized (mLock) {
mWakeLockSuspendBlocker = createSuspendBlockerLocked("PowerManagerService.WakeLocks");
mDisplaySuspendBlocker = createSuspendBlockerLocked("PowerManagerService.Display");
//防止cpu进入睡眠状态
mDisplaySuspendBlocker.acquire();
mHoldingDisplaySuspendBlocker = true;
mHalAutoSuspendModeEnabled = false;
mHalInteractiveModeEnabled = true;
//当前系统状态正常运行状态
mWakefulness = WAKEFULNESS_AWAKE;
nativeInit();
nativeSetAutoSuspend(false);
nativeSetInteractive(true);
}
}
构造函数比较简单，创建了一个接受消息处理的线程，cpu持锁不让手机睡眠，以及一些变量的初始化。
SystemServer创建完PowerManagerService后，继续调用SystemReady方法，再做一些初始化的工作，代码如下：
public void systemReady(IAppOpsService appOps) {
synchronized (mLock) {
mSystemReady = true;
mAppOps = appOps;
//android5.0后的新方法，localService可以直接取，在4.4中这样service是在init中传对象进来的
mDreamManager = getLocalService(DreamManagerInternal.class);
mDisplayManagerInternal = getLocalService(DisplayManagerInternal.class);
mPolicy = getLocalService(WindowManagerPolicy.class);
mBatteryManagerInternal = getLocalService(BatteryManagerInternal.class);
PowerManager pm = (PowerManager) mContext.getSystemService(Context.POWER_SERVICE);
//获取缺省、最大、最小屏幕亮度
mScreenBrightnessSettingMinimum = pm.getMinimumScreenBrightnessSetting();
mScreenBrightnessSettingMaximum = pm.getMaximumScreenBrightnessSetting();
mScreenBrightnessSettingDefault = pm.getDefaultScreenBrightnessSetting();
//创建sensorManager和sersorservice交互
SensorManager sensorManager = new SystemSensorManager(mContext, mHandler.getLooper());
// The notifier runs on the system server's main looper so as not to interfere
// with the animations and other critical functions of the power manager.
mBatteryStats = BatteryStatsService.getService();
mNotifier = new Notifier(Looper.getMainLooper(), mContext, mBatteryStats,
mAppOps, createSuspendBlockerLocked("PowerManagerService.Broadcasts"),
mPolicy);
//创建检测无线充电的对象
mWirelessChargerDetector = new WirelessChargerDetector(sensorManager,
createSuspendBlockerLocked("PowerManagerService.WirelessChargerDetector"),
mHandler);
mSettingsObserver = new SettingsObserver(mHandler);
mLightsManager = getLocalService(LightsManager.class);
mAttentionLight = mLightsManager.getLight(LightsManager.LIGHT_ID_ATTENTION);
// Initialize display power management.
mDisplayManagerInternal.initPowerManagement(
mDisplayPowerCallbacks, mHandler, sensorManager);
// Register for broadcasts from other components of the system.
//监听其他模块的广播
IntentFilter filter = new IntentFilter();
filter.addAction(Intent.ACTION_BATTERY_CHANGED);
filter.setPriority(IntentFilter.SYSTEM_HIGH_PRIORITY);
mContext.registerReceiver(new BatteryReceiver(), filter, null, mHandler);
filter = new IntentFilter();
filter.addAction(Intent.ACTION_DREAMING_STARTED);
filter.addAction(Intent.ACTION_DREAMING_STOPPED);
mContext.registerReceiver(new DreamReceiver(), filter, null, mHandler);
filter = new IntentFilter();
filter.addAction(Intent.ACTION_USER_SWITCHED);
mContext.registerReceiver(new UserSwitchedReceiver(), filter, null, mHandler);
filter = new IntentFilter();
filter.addAction(Intent.ACTION_DOCK_EVENT);
mContext.registerReceiver(new DockReceiver(), filter, null, mHandler);
// Register for settings changes.
final ContentResolver resolver = mContext.getContentResolver();
resolver.registerContentObserver(Settings.Secure.getUriFor(
Settings.Secure.SCREENSAVER_ENABLED),
false, mSettingsObserver, UserHandle.USER_ALL);
resolver.registerContentObserver(Settings.Secure.getUriFor(
Settings.Secure.SCREENSAVER_ACTIVATE_ON_SLEEP),
false, mSettingsObserver, UserHandle.USER_ALL);
resolver.registerContentObserver(Settings.Secure.getUriFor(
Settings.Secure.SCREENSAVER_ACTIVATE_ON_DOCK),
false, mSettingsObserver, UserHandle.USER_ALL);
resolver.registerContentObserver(Settings.System.getUriFor(
Settings.System.SCREEN_OFF_TIMEOUT),
false, mSettingsObserver, UserHandle.USER_ALL);
resolver.registerContentObserver(Settings.Secure.getUriFor(
Settings.Secure.SLEEP_TIMEOUT),
false, mSettingsObserver, UserHandle.USER_ALL);
resolver.registerContentObserver(Settings.Global.getUriFor(
Settings.Global.STAY_ON_WHILE_PLUGGED_IN),
false, mSettingsObserver, UserHandle.USER_ALL);
resolver.registerContentObserver(Settings.System.getUriFor(
Settings.System.SCREEN_BRIGHTNESS),
false, mSettingsObserver, UserHandle.USER_ALL);
resolver.registerContentObserver(Settings.System.getUriFor(
Settings.System.SCREEN_BRIGHTNESS_MODE),
false, mSettingsObserver, UserHandle.USER_ALL);
resolver.registerContentObserver(Settings.System.getUriFor(
Settings.System.SCREEN_AUTO_BRIGHTNESS_ADJ),
false, mSettingsObserver, UserHandle.USER_ALL);
resolver.registerContentObserver(Settings.Global.getUriFor(
Settings.Global.LOW_POWER_MODE),
false, mSettingsObserver, UserHandle.USER_ALL);
resolver.registerContentObserver(Settings.Global.getUriFor(
Settings.Global.LOW_POWER_MODE_TRIGGER_LEVEL),
false, mSettingsObserver, UserHandle.USER_ALL);
resolver.registerContentObserver(Settings.Global.getUriFor(
Settings.Global.THEATER_MODE_ON),
false, mSettingsObserver, UserHandle.USER_ALL);
// Go.
readConfigurationLocked();
updateSettingsLocked();
mDirty |= DIRTY_BATTERY_STATE;
updatePowerStateLocked();
}
}
从在android5.1.1中，service一般都会继承一个虚类SystemService，在其中定义了两个接口onStart和onBootPhase，分别是PowerManagerService启动的时候会调用，而onBootPhase会在系统启动的各个阶段来调用，下面我们分别来看看在powerManagerService中这两个函数的实现：
@Override
public void onStart() {
publishBinderService(Context.POWER_SERVICE, new BinderService());
publishLocalService(PowerManagerInternal.class, new LocalService());
Watchdog.getInstance().addMonitor(this);
Watchdog.getInstance().addThread(mHandler);
}
在onstart函数中，必须把一些接口publish，像在之前Binder的接口，都是通过PowerManagerService extends IPowerManager.Stub形式在PowerManagerService中实现接口
而在android5.1.1中都是通过方式重新定义一个类，然后把这个类publish出去。
private final class BinderService extends IPowerManager.Stub {
@Override // Binder call
public void acquireWakeLockWithUid(IBinder lock, int flags, String tag,
String packageName, int uid) {
if (uid < 0) {
uid = Binder.getCallingUid();
}
acquireWakeLock(lock, flags, tag, packageName, new WorkSource(uid), null);
}
@Override // Binder call
public void powerHint(int hintId, int data) {
if (!mSystemReady) {
// Service not ready yet, so who the heck cares about power hints, bah.
return;
}
mContext.enforceCallingOrSelfPermission(android.Manifest.permission.DEVICE_POWER, null);
powerHintInternal(hintId, data);
}
@Override // Binder call
public void acquireWakeLock(IBinder lock, int flags, String tag, String packageName,
WorkSource ws, String historyTag) {
。。。。。。。。。。。。。。而localservice都是一些本地的服务，不是通过Binder实现的。
我们接下来从，powerManager中的wakeLock说起，在powerManager中调用newWakeLock接口会生成一个WakeLock对象，而调用器acqure方法，最终会调用PowerManagerService中的acquireWakeLock方法
而具体的WakeLock有几种如下：
PARTIAL_WAKE_LOCK：只保持CPU运行，屏幕和键盘光关闭。
FULL_WAKE_LOCK:都不关闭
SCREEN_BRIGHT_WAKE_LOCK:屏幕背光不关闭，键盘光关闭
SCREEN_DIM_WAKE_LOCK：屏幕背光不关闭，键盘光关闭。但是屏幕背光可以变暗
PROXIMITY_SCREEN_OFF_WAKE_LOCK当持有这种类型wakelock，当距离传感器被遮挡，屏幕将被关闭。打电话时用这个功能
在PowerManagerService中的acquieWakeLock先要检查权限然后调用acquireWakeLockInternal接口，代码如下：
private void acquireWakeLockInternal(IBinder lock, int flags, String tag, String packageName,
WorkSource ws, String historyTag, int uid, int pid) {
synchronized (mLock) {
WakeLock wakeLock;
//查找wakelock
int index = findWakeLockIndexLocked(lock);
boolean notifyAcquire;
if (index >= 0) {查找到
wakeLock = mWakeLocks.get(index);
if (!wakeLock.hasSameProperties(flags, tag, ws, uid, pid)) {属性不一样，更新
// Update existing wake lock. This shouldn't happen but is harmless.
notifyWakeLockChangingLocked(wakeLock, flags, tag, packageName,
uid, pid, ws, historyTag);
wakeLock.updateProperties(flags, tag, packageName, ws, historyTag, uid, pid);
}
notifyAcquire = false;
} else {没找到，重新建立，添加
wakeLock = new WakeLock(lock, flags, tag, packageName, ws, historyTag, uid, pid);
try {
lock.linkToDeath(wakeLock, 0);
} catch (RemoteException ex) {
throw new IllegalArgumentException("Wake lock is already dead.");
}
mWakeLocks.add(wakeLock);
notifyAcquire = true;
}
//看是否需要点亮屏幕
applyWakeLockFlagsOnAcquireLocked(wakeLock, uid);
//整个PowermanagerService用来记录各个状态变化的一个标志位
mDirty |= DIRTY_WAKE_LOCKS;
//更新各个状态
updatePowerStateLocked();
if (notifyAcquire) {
// This needs to be done last so we are sure we have acquired the
// kernel wake lock. Otherwise we have a race where the system may
// go to sleep between the time we start the accounting in battery
// stats and when we actually get around to telling the kernel to
// stay awake.
notifyWakeLockAcquiredLocked(wakeLock);
}
}
}
整个PowermanagerService都是靠一个mDirty的各个标志位来记录各个状态的变化，随后会调用一个updatePowerStateLocked来更新各个状态。
同样解锁会调用到releaseWakeLockInternal，代码如下：
private void releaseWakeLockInternal(IBinder lock, int flags) {
synchronized (mLock) {
int index = findWakeLockIndexLocked(lock);
if (index < 0) {//没有找到退出
if (DEBUG_SPEW) {
Slog.d(TAG, "releaseWakeLockInternal: lock=" + Objects.hashCode(lock)
+ " [not found], flags=0x" + Integer.toHexString(flags));
}
return;
}
WakeLock wakeLock = mWakeLocks.get(index);
if (DEBUG_SPEW) {
Slog.d(TAG, "releaseWakeLockInternal: lock=" + Objects.hashCode(lock)
+ " [" + wakeLock.mTag + "], flags=0x" + Integer.toHexString(flags));
}
if ((flags & PowerManager.RELEASE_FLAG_WAIT_FOR_NO_PROXIMITY) != 0) {
mRequestWaitForNegativeProximity = true;
}
//去除wakelock
wakeLock.mLock.unlinkToDeath(wakeLock, 0);
removeWakeLockLocked(wakeLock, index);
}
}
PowerManagerService中最终各个接口都会调一个函数updatePowerStateLocked，主要用来更新power的各个状态
private void updatePowerStateLocked() {
if (!mSystemReady || mDirty == 0) {各个状态没有变化
return;
}
if (!Thread.holdsLock(mLock)) {
Slog.wtf(TAG, "Power manager lock was not held when calling updatePowerStateLocked");
}
Trace.traceBegin(Trace.TRACE_TAG_POWER, "updatePowerState");
try {
// Phase 0: Basic state updates.
//更新充电的各个状态(是否充电、电池电量、充电方式、是否低电量)，以及更新低功耗模式（android5.0增加的）
updateIsPoweredLocked(mDirty);
//更新mStayOn状态，为true，屏幕常亮
updateStayOnLocked(mDirty);
//更新屏幕是否最亮的状态是否持续
updateScreenBrightnessBoostLocked(mDirty);
// Phase 1: Update wakefulness.
// Loop because the wake lock and user activity computations are influenced
// by changes in wakefulness.
final long now = SystemClock.uptimeMillis();
int dirtyPhase2 = 0;
for (;;) {
int dirtyPhase1 = mDirty;
dirtyPhase2 |= dirtyPhase1;
mDirty = 0;
//更新mWakeLockSummary的状态
updateWakeLockSummaryLocked(dirtyPhase1);
//更新mUserActivitySummary状态
updateUserActivitySummaryLocked(now, dirtyPhase1);
if (!updateWakefulnessLocked(dirtyPhase1)) {
break;
}
}
// Phase 2: Update display power state.
boolean displayBecameReady = updateDisplayPowerStateLocked(dirtyPhase2);//更新display状态，在displaypowercontrol中会控制亮度，灭屏等
// Phase 3: Update dream state (depends on display ready signal).
//更新梦的状态，用dreammanager控制梦，powermanagerservice中记录mWakefulness
updateDreamLocked(dirtyPhase2, displayBecameReady);
// Phase 4: Send notifications, if needed.
if (mDisplayReady) {
finishWakefulnessChangeLocked();
}
// Phase 5: Update suspend blocker.
// Because we might release the last suspend blocker here, we need to make sure
// we finished everything else first!
//更新睡眠锁，以及是否持锁和释放锁
updateSuspendBlockerLocked();
} finally {
Trace.traceEnd(Trace.TRACE_TAG_POWER);
}
}
updateIsPoweredLocked、updateStayOnLocked、updateScreenBrightnessBoostLocked、updateWakeLockSummaryLocked、updateUserActivitySummaryLocked都是比较简单、在上面的函数注释中都有介绍。下面我们先看下updateWakefulnessLocked函数，代码如下：
private boolean updateWakefulnessLocked(int dirty) {
boolean changed = false;
if ((dirty & (DIRTY_WAKE_LOCKS | DIRTY_USER_ACTIVITY | DIRTY_BOOT_COMPLETED
| DIRTY_WAKEFULNESS | DIRTY_STAY_ON | DIRTY_PROXIMITY_POSITIVE
| DIRTY_DOCK_STATE)) != 0) {
//当前状态是醒着，并且准备开始睡眠了
if (mWakefulness == WAKEFULNESS_AWAKE && isItBedTimeYetLocked()) {
if (DEBUG_SPEW) {
Slog.d(TAG, "updateWakefulnessLocked: Bed time...");
}
final long time = SystemClock.uptimeMillis();
//是应该开始做梦，还是先睡眠
if (shouldNapAtBedTimeLocked()) {
//当前状态设置为睡眠状态
changed = napNoUpdateLocked(time, Process.SYSTEM_UID);
} else {
//当前状态设置为假寐状态
changed = goToSleepNoUpdateLocked(time,
PowerManager.GO_TO_SLEEP_REASON_TIMEOUT, 0, Process.SYSTEM_UID);
}
}
}
return changed;
}
private boolean isBeingKeptAwakeLocked() {
return mStayOn
|| mProximityPositive//距离传感器
|| (mWakeLockSummary & WAKE_LOCK_STAY_AWAKE) != 0//wakelock锁
|| (mUserActivitySummary & (USER_ACTIVITY_SCREEN_BRIGHT
| USER_ACTIVITY_SCREEN_DIM)) != 0//用户行为、和用户点击屏幕、自动灭屏时间等有关
|| mScreenBrightnessBoostInProgress;\\是否要保持处于最亮状态
}
private boolean isItBedTimeYetLocked() {
//当启动完成、并且设备不必保持唤醒状态是的时候返回true
return mBootCompleted && !isBeingKeptAwakeLocked();
}
updateDreamLocked函数通过发送消息，最终会调用handleSandman：
private void handleSandman() { // runs on handler thread
// Handle preconditions.
final boolean startDreaming;
final int wakefulness;
synchronized (mLock) {
mSandmanScheduled = false;
wakefulness = mWakefulness;
if (mSandmanSummoned && mDisplayReady) {
startDreaming = canDreamLocked() || canDozeLocked();
mSandmanSummoned = false;
} else {
startDreaming = false;
}
}
// Start dreaming if needed.
// We only control the dream on the handler thread, so we don't need to worry about
// concurrent attempts to start or stop the dream.
final boolean isDreaming;
if (mDreamManager != null) {
// Restart the dream whenever the sandman is summoned.
if (startDreaming) {
mDreamManager.stopDream(false /*immediate*/);
mDreamManager.startDream(wakefulness == WAKEFULNESS_DOZING);
}
isDreaming = mDreamManager.isDreaming();
} else {
isDreaming = false;
}
// Update dream state.
synchronized (mLock) {
// Remember the initial battery level when the dream started.
if (startDreaming && isDreaming) {
mBatteryLevelWhenDreamStarted = mBatteryLevel;
if (wakefulness == WAKEFULNESS_DOZING) {
Slog.i(TAG, "Dozing...");
} else {
Slog.i(TAG, "Dreaming...");
}
}
// If preconditions changed, wait for the next iteration to determine
// whether the dream should continue (or be restarted).
if (mSandmanSummoned || mWakefulness != wakefulness) {
return; // wait for next cycle
}
// Determine whether the dream should continue.
if (wakefulness == WAKEFULNESS_DREAMING) {
if (isDreaming && canDreamLocked()) {
//在做梦中
if (mDreamsBatteryLevelDrainCutoffConfig >= 0
&& mBatteryLevel < mBatteryLevelWhenDreamStarted
- mDreamsBatteryLevelDrainCutoffConfig
&& !isBeingKeptAwakeLocked()) {
// If the user activity timeout expired and the battery appears
// to be draining faster than it is charging then stop dreaming
// and go to sleep.
Slog.i(TAG, "Stopping dream because the battery appears to "
+ "be draining faster than it is charging. "
+ "Battery level when dream started: "
+ mBatteryLevelWhenDreamStarted + "%. "
+ "Battery level now: " + mBatteryLevel + "%.");
} else {
//继续做梦
return; // continue dreaming
}
}
// Dream has ended or will be stopped. Update the power state.
//结束做梦，要么唤醒、要么继续goToSleep
if (isItBedTimeYetLocked()) {
goToSleepNoUpdateLocked(SystemClock.uptimeMillis(),
PowerManager.GO_TO_SLEEP_REASON_TIMEOUT, 0, Process.SYSTEM_UID);
updatePowerStateLocked();
} else {
wakeUpNoUpdateLocked(SystemClock.uptimeMillis(), Process.SYSTEM_UID);
updatePowerStateLocked();
}
} else if (wakefulness == WAKEFULNESS_DOZING) {
if (isDreaming) {
return; // continue dozing
}
//直接睡眠，跳过做梦
// Doze has ended or will be stopped. Update the power state.
reallyGoToSleepNoUpdateLocked(SystemClock.uptimeMillis(), Process.SYSTEM_UID);
updatePowerStateLocked();
}
}
// Stop dream.能走到这说明，肯定结束做梦
if (isDreaming) {
mDreamManager.stopDream(false /*immediate*/);
}
}
updateSuspendBlockerLocked函数是是否要Cpu持锁。
private void updateSuspendBlockerLocked() {
final boolean needWakeLockSuspendBlocker = ((mWakeLockSummary & WAKE_LOCK_CPU) != 0);//是否要cpu持锁
final boolean needDisplaySuspendBlocker = needDisplaySuspendBlockerLocked();//是否display要持锁
final boolean autoSuspend = !needDisplaySuspendBlocker;
final boolean interactive = mDisplayPowerRequest.isBrightOrDim();
// Disable auto-suspend if needed.
// FIXME We should consider just leaving auto-suspend enabled forever since
// we already hold the necessary wakelocks.
if (!autoSuspend && mDecoupleHalAutoSuspendModeFromDisplayConfig) {
setHalAutoSuspendModeLocked(false);
}
// First acquire suspend blockers if needed.
if (needWakeLockSuspendBlocker && !mHoldingWakeLockSuspendBlocker) {
mWakeLockSuspendBlocker.acquire();
mHoldingWakeLockSuspendBlocker = true;
}
if (needDisplaySuspendBlocker && !mHoldingDisplaySuspendBlocker) {
mDisplaySuspendBlocker.acquire();
mHoldingDisplaySuspendBlocker = true;
}
// Inform the power HAL about interactive mode.
// Although we could set interactive strictly based on the wakefulness
// as reported by isInteractive(), it is actually more desirable to track
// the display policy state instead so that the interactive state observed
// by the HAL more accurately tracks transitions between AWAKE and DOZING.
// Refer to getDesiredScreenPolicyLocked() for details.
if (mDecoupleHalInteractiveModeFromDisplayConfig) {
// When becoming non-interactive, we want to defer sending this signal
// until the display is actually ready so that all transitions have
// completed. This is probably a good sign that things have gotten
// too tangled over here...
if (interactive || mDisplayReady) {//当屏幕亮着|| 当屏幕暗着，displayPowerControl准备好了，进入该条件设置
setHalInteractiveModeLocked(interactive);
}
}
// Then release suspend blockers if needed.
if (!needWakeLockSuspendBlocker && mHoldingWakeLockSuspendBlocker) {
mWakeLockSuspendBlocker.release();
mHoldingWakeLockSuspendBlocker = false;
}
if (!needDisplaySuspendBlocker && mHoldingDisplaySuspendBlocker) {
mDisplaySuspendBlocker.release();
mHoldingDisplaySuspendBlocker = false;
}
// Enable auto-suspend if needed.
if (autoSuspend && mDecoupleHalAutoSuspendModeFromDisplayConfig) {
setHalAutoSuspendModeLocked(true);
}
}
下来介绍下powermanager中其他的接口，
1、gotosleep，让设备睡眠，按power键会调用这个函数
private void goToSleepInternal(long eventTime, int reason, int flags, int uid) {
synchronized (mLock) {
//返回true，才更新状态
if (goToSleepNoUpdateLocked(eventTime, reason, flags, uid)) {
updatePowerStateLocked();
}
}
}
@SuppressWarnings("deprecation")
private boolean goToSleepNoUpdateLocked(long eventTime, int reason, int flags, int uid) {
if (DEBUG_SPEW) {
Slog.d(TAG, "goToSleepNoUpdateLocked: eventTime=" + eventTime
+ ", reason=" + reason + ", flags=" + flags + ", uid=" + uid);
}
if (eventTime < mLastWakeTime
|| mWakefulness == WAKEFULNESS_ASLEEP
|| mWakefulness == WAKEFULNESS_DOZING
|| !mBootCompleted || !mSystemReady) {
return false;
}
Trace.traceBegin(Trace.TRACE_TAG_POWER, "goToSleep");
try {
switch (reason) {//说明原因
case PowerManager.GO_TO_SLEEP_REASON_DEVICE_ADMIN:
Slog.i(TAG, "Going to sleep due to device administration policy "
+ "(uid " + uid +")...");
break;
。。。。。。。。。。。。。
}
mLastSleepTime = eventTime;
mSandmanSummoned = true;
setWakefulnessLocked(WAKEFULNESS_DOZING, reason);
// Report the number of wake locks that will be cleared by going to sleep.
//统计wakelock的数量
int numWakeLocksCleared = 0;
final int numWakeLocks = mWakeLocks.size();
for (int i = 0; i < numWakeLocks; i++) {
final WakeLock wakeLock = mWakeLocks.get(i);
switch (wakeLock.mFlags & PowerManager.WAKE_LOCK_LEVEL_MASK) {
case PowerManager.FULL_WAKE_LOCK:
case PowerManager.SCREEN_BRIGHT_WAKE_LOCK:
case PowerManager.SCREEN_DIM_WAKE_LOCK:
numWakeLocksCleared += 1;
break;
}
}
EventLog.writeEvent(EventLogTags.POWER_SLEEP_REQUESTED, numWakeLocksCleared);
// Skip dozing if requested.
//直接进入睡眠
if ((flags & PowerManager.GO_TO_SLEEP_FLAG_NO_DOZE) != 0) {
reallyGoToSleepNoUpdateLocked(eventTime, uid);
}
} finally {
Trace.traceEnd(Trace.TRACE_TAG_POWER);
}
return true;
}
2、useractivity是当用户点击屏幕等行为，会重新计算自动灭屏的时间等，然后回去updatepowerstate
3、wakeup唤醒设备，与gotosleep对应。
4、nap，使设备处于一种假寐的状态
5、boostScreenBrightness，是屏幕达到最亮持续一段时间
这其中每个函数都会调用updatepowerstate