Android60 亮屏灭屏流程(二)亮度设置

1、Android6.0 亮屏灭屏流程(DisplayPowerControler、WMS)(二)亮度设置从这个函数开始分析，主要分析下亮度的设置流程。cpp view plain copy 在 CODE 上查看代码片派生到我的代码片 public void setScreenState(int state) if (mScreenState != state) if (DEBUG) Slog.d(TAG, setScreenState: state= + state);mScreenState = state;mScreenReady = false; scheduleScreenUpdate(

2、);scheduleScreenUpdate 主要通过消息方式，最后调用到下面函数。当我们屏幕刚要点亮，这 个时候 mScreenBrightness 为 0，所以这个时候调用 mPhotonicModulator.setState 设置 state 是 点亮，但是 brightness 是 0 的。cpp view plain copy 在 CODE 上查看代码片派生到我的代码片 private final Runnable mScreenUpdateRunnable = new Runnable() Override public void run() mScreenUpdatePendi

3、ng = false;int brightness = mScreenState != Display.STATE_OFF& mColorFadeLevel 0f ? mScreenBrightness : 0;if (mPhotonicModulator.setState(mScreenState, brightness) if (DEBUG) Slog.d(TAG, Screen ready); mScreenReady = true; invokeCleanListenerIfNeeded(); else if (DEBUG) Slog.d(TAG, Screen not ready);

4、DisplayPowerState 的设置亮度状态逻辑分析 mPhotonicModulator.setState 应该要 PhotonicModulator 的 run 函数结合一起看。cpp view plain copy 在 CODE 上查看代码片派生到我的代码片public boolean setState(int state, int backlight) synchronized (mLock) boolean stateChanged = state != mPendingState;boolean backlightChanged = backlight != mPending

5、Backlight;if (stateChanged | backlightChanged) if (DEBUG) Slog.d(TAG, Requesting new screen state: state=+ Display.stateToString(state) + , backlight= + backlight);mPendingState = state;mPendingBacklight = backlight;boolean changeInProgress = mStateChangeInProgress | mBacklightChangeInProgress;mStat

6、eChangeInProgress = stateChanged;mBacklightChangeInProgress = backlightChanged;if (!changeInProgress) Slog.d(TAG,notify set backlight thread run);mLock.notifyAll();return !mStateChangeInProgress;两者结合看先 setState 设置了状态，只有状态改变时，我们才能重新设置状态(设置到 mpendingState 和 mPendingBacklight)。而在 run 函数中，当设置的状态 mPendin

7、gState、 mPendingBacklight 和 mActualState、mActualBacklight (真正设置到背光的状态、亮度)不 一样时，才会调用 mBlanker.requestDisplayState 设置亮度。否则状态没有改变，就会把 mStateChangeInProgress 和 mBacklightChangeInProgress 设置为 false，然后线程就 wait 住。 而此时 setState 重新设置下来的话，这个时候把亮度和状态设置到 mPendingState 和 mPendingBacklight 。然后这时 mStateChangeInPro

8、gress 和 mBacklightChangeInProgress 都是 false。这样就可以调用mLock的notifyAll函数重新唤醒线程，这样就把把前面setState设置 下来的 mPendingState 和 mPendingBacklight 再通过 mBlanker.requestDisplayState设置到背光 设备中去。cpp view plain copy 在 CODE 上查看代码片派生到我的代码片Overridepublic void run() for (;) / Get pending change.final int state;final boolean

9、stateChanged;final int backlight;final boolean backlightChanged;synchronized (mLock) state = mPendingState;stateChanged = (state != mActualState); backlight = mPendingBacklight;backlightChanged = (backlight != mActualBacklight); if (!stateChanged) / State changed applied, notify outer class. postScr

10、eenUpdateThreadSafe(); mStateChangeInProgress = false;if (!backlightChanged) mBacklightChangeInProgress = false;if (!stateChanged & !backlightChanged) try mLock.wait(); catch (InterruptedException ex) continue;mActualState = state; mActualBacklight = backlight;/ Apply pending change.if (true) Slog.d

11、(TAG, Updating screen state: state=+ Display.stateToString(state) + , backlight= + backlight); mBlanker.requestDisplayState(state, backlight); Slog.d(TAG, kangchen Updating screen state: state=);设置亮度、状态到背光设备DisplayBlanker 的 requestDisplayState 如下，主要调用 requestGlobalDisplayStateInternal 函数。 cpp view p

12、lain copy 在 CODE 上查看代码片派生到我的代码片DisplayBlanker blanker = new DisplayBlanker() Overridepublic void requestDisplayState(int state, int brightness) / The order of operations is important for legacy reasons.if (state = Display.STATE_OFF) requestGlobalDisplayStateInternal(state, brightness);callbacks.onDi

13、splayStateChange(state);if (state != Display.STATE_OFF) requestGlobalDisplayStateInternal(state, brightness);requestGlobalDisplayStatelnternal函数先是对state和brightness的处理，然后把这个两个变量 放 在 mGlobalDisplayState 和 mGlobalDisplayBrightness 成 员 变 量 中 。 紧 接 着 调 用 applyGlobalDisplayStateLocked 函数 mTempDisplayState

14、WorkQueue 作为参数。最后再调用 mTempDisplayStateWorkQueue各个成员的run函数(这里返回的是Runnable接口，这里就 会设置状态和亮度到设备中去)。cpp view plain copy 在 CODE 上查看代码片派生到我的代码片private void requestGlobalDisplayStateInternal(int state, int brightness) if (state = Display.STATE_UNKNOWN) state = Display.STATE_ON;if (state = Display.STATE_OFF)

15、brightness = PowerManager.BRIGHTNESS_OFF; else if (brightness PowerManager.BRIGHTNESS_ON) brightness = PowerManager.BRIGHTNESS_ON;synchronized (mTempDisplayStateWorkQueue) try synchronized (mSyncRoot) if (mGlobalDisplayState = state& mGlobalDisplayBrightness = brightness) return; / no changemGlobalD

16、isplayState = state;mGlobalDisplayBrightness = brightness; applyGlobalDisplayStateLocked(mTempDisplayStateWorkQueue);/ Setting the display power state can take hundreds of milliseconds/ to complete so we defer the most expensive part of the work until/ after we have exited the critical section to av

17、oid blocking other/ threads for a long time.for (int i = 0; i mTempDisplayStateWorkQueue.size(); i+) mTempDisplayStateWorkQueue.get(i).run();/设置亮度、状态到设备 finally mTempDisplayStateWorkQueue.clear();applyGlobalDisplayStateLocked 函 数 会 遍 历 各 个 显 示 设 备 ( 多 显 示 )， 然 后 调 用 updateDisplayStateLocked函数返回一个 Ru

18、nnable，最后把这个 Runnable放入之前传入的 mTempDisplayStateWorkQueue 队列中。cpp view plain copy 在 CODE 上查看代码片派生到我的代码片private void applyGlobalDisplayStateLocked(List workQueue) final int count = mDisplayDevices.size();for (int i = 0; i count; i+) DisplayDevice device = mDisplayDevices.get(i);Runnable runnable = upda

19、teDisplayStateLocked(device);if (runnable != null) workQueue.add(runnable);那下面我们看下 updateDisplayStateLocked 函 数， 主要是调用了 DisplayDevice 的 requestDisplayStateLocked 函数，当然 mGlobalDisplayState 和 mGlobalDisplayBrightness 作为 参数。cpp view plain copy 在 CODE 上查看代码片派生到我的代码片private Runnable updateDisplayStateLoc

20、ked(DisplayDevice device) / Blank or unblank the display immediately to match the state requested/ by the display power controller (if known).DisplayDeviceInfo info = device.getDisplayDeviceInfoLocked();if (info.flags & DisplayDeviceInfo.FLAG_NEVER_BLANK) = 0) returndevice.requestDisplayStateLocked(

21、mGlobalDisplayState,mGlobalDisplayBrightness);return null;这里的 DisplayDevice 的 requestDisplayStateLocked 函数，是在 LocalDisplayAdapter 中实现的， 这里吧 state 和 brightness 保存在 mState 和 mBrightness 中，然后返回 Runnable 接口，最后 在 Runnable 接口中设置亮度和状态。cpp view plain copy 在 CODE 上查看代码片派生到我的代码片public Runnable requestDisplayS

22、tateLocked(final int state, final int brightness) / Assume that the brightness is off if the display is being turned off.assert state != Display.STATE_OFF | brightness = PowerManager.BRIGHTNESS_OFF;final boolean stateChanged = (mState != state);final boolean brightnessChanged = (mBrightness != brigh

23、tness) & mBacklight != null; if (stateChanged | brightnessChanged) final int displayId = mBuiltInDisplayId;final IBinder token = getDisplayTokenLocked();final int oldState = mState;if (stateChanged) mState = state;/保存 stateupdateDeviceInfoLocked();if (brightnessChanged) mBrightness = brightness;/保存

24、brightness/ Defer actually setting the display state until after we have exited/ the critical section since it can take hundreds of milliseconds/ to complete.return new Runnable() /返回 RunnableOverridepublic void run() / Exit a suspended state before making any currentState = oldState;if (Display.isS

25、uspendedState(oldState)| oldState = Display.STATE_UNKNOWN) if (!Display.isSuspendedState(state) setDisplayState(state); currentState = state; else if (state = Display.STATE_DOZE_SUSPEND| oldState = Display.STATE_DOZE_SUSPEND) setDisplayState(Display.STATE_DOZE);currentState = Display.STATE_DOZE; els

26、e return; / old state and new state is off/ Apply brightness changes given that we are in a non-suspended state. if (brightnessChanged) Slog.d(TAG, kangchen setDisplayBrightnessbrightness1= brightness);setDisplayBrightness(brightness);Slog.d(TAG, kangchen setDisplayBrightnessbrightness2= +brightness

27、);/ Enter the final desired state, possibly suspended.if (state != currentState) setDisplayState(state);private void setDisplayState(int state) if (DEBUG) Slog.d(TAG, setDisplayState(+ id= + displayId+ , state= + Display.stateToString(state) + );try final int mode = getPowerModeForState(state);Surfa

28、ceControl.setDisplayPowerMode(token, mode);/至U SurfaceControl 设置状态 finally Trace.traceEnd(Trace.TRACE_TAG_POWER);private void setDisplayBrightness(int brightness) try mBacklight.setBrightness(brightness);/设 置亮度 finally Trace.traceEnd(Trace.TRACE_TAG_POWER);return null;DisplayPowerControl设置亮度逻辑(根据VSy

29、nc信号将亮度慢慢变亮)上面在 DisplayPowerState 中仅仅是设置状态，比如刚点亮屏幕这个时候其实设置的brightness 为 0,我们继续分析 DisplayPowerState 的 updatePowerState 函数。在 updatePowerState 函数中，当设置亮度时会调用如下代码：cpp view plain copy 在 CODE 上查看代码片派生至我的代码片if (!mPendingScreenOff) if (state = Display.STATE_ON | state = Display.STATE_DOZE) animateScreenBrigh

30、tness(brightness,slowChange ? BRIGHTNESS_RAMP_RATE_SLOW : BRIGHTNESS_RAMP_RATE_FAST); else animateScreenBrightness(brightness, 0);我 们 注 意 到 这 里 有 一 个 BRIGHTNESS_RAMP_RATE_SLOW 和 BRIGHTNESS_RAMP_RATE_FAST (这里涉及到亮度显示原理我们后面分析)，先看 animateScreenBrightness函数 。 这 里 函 数 主 要 调 用了mScreenBrightnessRampAnimator

31、.animateTo 函数。cpp view plain copy 在 CODE 上查看代码片派生到我的代码片private void animateScreenBrightness(int target, int rate) if (mScreenBrightnessRampAnimator.animateTo(target, rate) try mBatteryStats.noteScreenBrightness(target); catch (RemoteException ex) / same process我们再来看 mScreenBrightnessRampAnimator 对象的

32、创建cpp view plain copy 在 CODE 上查看代码片派生到我的代码片 mScreenBrightnessRampAnimator = new RampAnimator(mPowerState, DisplayPowerState.SCREEN_BRIGHTNESS);我 们 注 意 一 个 参 数 是 DisplayPowerState 对 象 mPowerState ， 另 一 个 参 数 是 DisplayPowerState.SCREEN_BRIGHTNESScpp view plain copy 在 CODE 上查看代码片派生到我的代码片public static f

33、inal IntProperty SCREEN_BRIGHTNESS =new IntProperty(screenBrightness) Overridepublic void setValue(DisplayPowerState object, int value) object.setScreenBrightness(value);Overridepublic Integer get(DisplayPowerState object) return object.getScreenBrightness();RampAnimator 的构造函数。cpp view plain copy 在

34、CODE 上查看代码片派生到我的代码片public RampAnimator(T object, IntProperty property) mObject = object;mProperty = property; mChoreographer = Choreographer.getInstance();我们结合 RampAnimator 的构造函数，再来分析 RampAnimator 的 animateTo 函数。当ratev=O时，这个时候，我们直接调用mProperty.setValue。就是调用DisplayPowerState 的 setScreenBrightness 函数。这

35、个 setScreenBrightness 函数我们后面分析。当rate0时，这个时候会调用postAnimationCallback函数(这个函数根据VSync信号过 来，把亮度慢慢上升的一个过程)，而且mAnimating置为true。cpp view plain copy 在 CODE 上查看代码片派生到我的代码片 public boolean animateTo(int target, int rate) / Immediately jump to the target the first time.if (mFirstTime | rate mRate| (target = mCur

36、rentValue & mCurrentValue = mTargetValue)| (mTargetValue = mCurrentValue & mCurrentValue mCurrentValue) mAnimatedValue = Math.min(mAnimatedValue + amount, mTargetValue); else mAnimatedValue = Math.max(mAnimatedValue - amount, mTargetValue); final int oldCurrentValue = mCurrentValue; mCurrentValue = Math.round(mAnimatedValue);if (oldCurrentValue != mCurrentValue) mProperty.setValue(mObject, mCurrentValue);/ 设 置 到 DisplayPowerS