android5.1 PowerManagerService和DisplayPowerControler、DisplayPowerState关系.doc

android5.1 PowerManagerService和DisplayPowerControler、DisplayPowerState关系PowerManagerService在updateDisplayPowerStateLocked中与DisplayPowerControler交互，详细看代码：java view plain copyprivate boolean updateDisplayPowerStateLocked(int dirty) final boolean oldDisplayReady = mDisplayReady; if (dirty & (DIRTY_WAKE_LOCKS | DIRTY_USER_ACTIVITY | DIRTY_WAKEFULNESS | DIRTY_ACTUAL_DISPLAY_POWER_STATE_UPDATED | DIRTY_BOOT_COMPLETED | DIRTY_SETTINGS | DIRTY_SCREEN_BRIGHTNESS_BOOST) != 0) mDisplayPowerRequest.policy = getDesiredScreenPolicyLocked(); / Determine appropriate screen brightness and auto-brightness adjustments. int screenBrightness = mScreenBrightnessSettingDefault; float screenAutoBrightnessAdjustment = 0.0f; boolean autoBrightness = (mScreenBrightnessModeSetting = Settings.System.SCREEN_BRIGHTNESS_MODE_AUTOMATIC); if (isValidBrightness(mScreenBrightnessOverrideFromWindowManager) screenBrightness = mScreenBrightnessOverrideFromWindowManager; autoBrightness = false; else if (isValidBrightness(mTemporaryScreenBrightnessSettingOverride) screenBrightness = mTemporaryScreenBrightnessSettingOverride; else if (isValidBrightness(mScreenBrightnessSetting) screenBrightness = mScreenBrightnessSetting; if (autoBrightness) screenBrightness = mScreenBrightnessSettingDefault; if (isValidAutoBrightnessAdjustment( mTemporaryScreenAutoBrightnessAdjustmentSettingOverride) screenAutoBrightnessAdjustment = mTemporaryScreenAutoBrightnessAdjustmentSettingOverride; else if (isValidAutoBrightnessAdjustment( mScreenAutoBrightnessAdjustmentSetting) screenAutoBrightnessAdjustment = mScreenAutoBrightnessAdjustmentSetting; screenBrightness = Math.max(Math.min(screenBrightness, mScreenBrightnessSettingMaximum), mScreenBrightnessSettingMinimum); screenAutoBrightnessAdjustment = Math.max(Math.min( screenAutoBrightnessAdjustment, 1.0f), -1.0f); / Update display power request. mDisplayPowerRequest.screenBrightness = screenBrightness; mDisplayPowerRequest.screenAutoBrightnessAdjustment = screenAutoBrightnessAdjustment; mDisplayPowerRequest.useAutoBrightness = autoBrightness; mDisplayPowerRequest.useProximitySensor = shouldUseProximitySensorLocked(); mDisplayPowerRequest.lowPowerMode = mLowPowerModeEnabled; mDisplayPowerRequest.boostScreenBrightness = mScreenBrightnessBoostInProgress; if (mDisplayPowerRequest.policy = DisplayPowerRequest.POLICY_DOZE) mDisplayPowerRequest.dozeScreenState = mDozeScreenStateOverrideFromDreamManager; mDisplayPowerRequest.dozeScreenBrightness = mDozeScreenBrightnessOverrideFromDreamManager; else mDisplayPowerRequest.dozeScreenState = Display.STATE_UNKNOWN; mDisplayPowerRequest.dozeScreenBrightness = PowerManager.BRIGHTNESS_DEFAULT; mDisplayReady = mDisplayManagerInternal.requestPowerState(mDisplayPowerRequest,/调用DisplayPowerControler的requestPowerstate接口 mRequestWaitForNegativeProximity); mRequestWaitForNegativeProximity = false; return mDisplayReady & !oldDisplayReady; 接下来我们再看看mDisplayManagerInternal这个成员变量：在systemready中java view plain copymDisplayManagerInternal = getLocalService(DisplayManagerInternal.class); 。 mDisplayManagerInternal.initPowerManagement( mDisplayPowerCallbacks, mHandler, sensorManager); 而DisplayPowerControler是在DisplayManagerService中定义，并且放在localservice中，publish出来。java view plain copy private final class LocalService extends DisplayManagerInternal Override public void initPowerManagement(final DisplayPowerCallbacks callbacks, Handler handler, SensorManager sensorManager) synchronized (mSyncRoot) DisplayBlanker blanker = new DisplayBlanker() Override public void requestDisplayState(int state) / The order of operations is important for legacy reasons. if (state = Display.STATE_OFF) requestGlobalDisplayStateInternal(state); callbacks.onDisplayStateChange(state);/注意这个接口后续会介绍 if (state != Display.STATE_OFF) requestGlobalDisplayStateInternal(state); ; mDisplayPowerController = new DisplayPowerController(/new一个DisplayPowerController mContext, callbacks, handler, sensorManager, blanker); Override public boolean requestPowerState(DisplayPowerRequest request, boolean waitForNegativeProximity) return mDisplayPowerController.requestPowerState(request, waitForNegativeProximity); 。 好接下来我们先分析DisplayPowerControler中的requestPowerState函数：java view plain copypublic boolean requestPowerState(DisplayPowerRequest request, boolean waitForNegativeProximity) synchronized (mLock) boolean changed = false; if (waitForNegativeProximity & !mPendingWaitForNegativeProximityLocked) mPendingWaitForNegativeProximityLocked = true; changed = true; if (mPendingRequestLocked = null) mPendingRequestLocked = new DisplayPowerRequest(request); changed = true; else if (!mPendingRequestLocked.equals(request) mPendingRequestLocked.copyFrom(request); changed = true; if (changed) mDisplayReadyLocked = false;/注意有变化，返回的是false if (changed & !mPendingRequestChangedLocked) mPendingRequestChangedLocked = true; sendUpdatePowerStateLocked();/发送信号，到updatePowerState return mDisplayReadyLocked; 下面我们就来分析下DisplayPowerControler中的updatePowerState函数：java view plain copyprivate void updatePowerState() / Update the power state request. final boolean mustNotify; boolean mustInitialize = false; boolean autoBrightnessAdjustmentChanged = false; synchronized (mLock) mPendingUpdatePowerStateLocked = false; if (mPendingRequestLocked = null) return; / wait until first actual power request if (mPowerRequest = null) mPowerRequest = new DisplayPowerRequest(mPendingRequestLocked); mWaitingForNegativeProximity = mPendingWaitForNegativeProximityLocked; mPendingWaitForNegativeProximityLocked = false; mPendingRequestChangedLocked = false; mustInitialize = true; else if (mPendingRequestChangedLocked) autoBrightnessAdjustmentChanged = (mPowerRequest.screenAutoBrightnessAdjustment != mPendingRequestLocked.screenAutoBrightnessAdjustment); mPowerRequest.copyFrom(mPendingRequestLocked); mWaitingForNegativeProximity |= mPendingWaitForNegativeProximityLocked; mPendingWaitForNegativeProximityLocked = false; mPendingRequestChangedLocked = false; mDisplayReadyLocked = false;/这时候mDisplayReadyLocked还是false，这是requestPowerState的返回值 mustNotify = !mDisplayReadyLocked; / Initialize things the first time the power state is changed. if (mustInitialize) initialize(); / Compute the basic display state using the policy. / We might override this below based on other factors. int state; int brightness = PowerManager.BRIGHTNESS_DEFAULT; boolean performScreenOffTransition = false; switch (mPowerRequest.policy) /根据policy，得到显示的state case DisplayPowerRequest.POLICY_OFF: state = Display.STATE_OFF; performScreenOffTransition = true; break; case DisplayPowerRequest.POLICY_DOZE: if (mPowerRequest.dozeScreenState != Display.STATE_UNKNOWN) state = mPowerRequest.dozeScreenState; else state = Display.STATE_DOZE; if (!mAllowAutoBrightnessWhileDozingConfig) brightness = mPowerRequest.dozeScreenBrightness; break; case DisplayPowerRequest.POLICY_DIM: case DisplayPowerRequest.POLICY_BRIGHT: default: state = Display.STATE_ON; break; assert(state != Display.STATE_UNKNOWN); / Apply the proximity sensor.这块是距离传感器 if (mProximitySensor != null) if (mPowerRequest.useProximitySensor & state != Display.STATE_OFF) setProximitySensorEnabled(true); if (!mScreenOffBecauseOfProximity & mProximity = PROXIMITY_POSITIVE) mScreenOffBecauseOfProximity = true; sendOnProximityPositiveWithWakelock(); else if (mWaitingForNegativeProximity & mScreenOffBecauseOfProximity & mProximity = PROXIMITY_POSITIVE & state != Display.STATE_OFF) setProximitySensorEnabled(true); else setProximitySensorEnabled(false); mWaitingForNegativeProximity = false; if (mScreenOffBecauseOfProximity & mProximity != PROXIMITY_POSITIVE) mScreenOffBecauseOfProximity = false; sendOnProximityNegativeWithWakelock(); else mWaitingForNegativeProximity = false; if (mScreenOffBecauseOfProximity) state = Display.STATE_OFF; / Animate the screen state change unless already animating. / The transition may be deferred, so after this point we will use the / actual state instead of the desired one. /后面详细分析下这函数，主要设置显示的state，和displayPowerState交互。 animateScreenStateChange(state, performScreenOffTransition); state = mPowerState.getScreenState(); / Use zero brightness when screen is off. if (state = Display.STATE_OFF) brightness = PowerManager.BRIGHTNESS_OFF; / Configure auto-brightness. boolean autoBrightnessEnabled = false; if (mAutomaticBrightnessController != null) final boolean autoBrightnessEnabledInDoze = mAllowAutoBrightnessWhileDozingConfig & (state = Display.STATE_DOZE | state = Display.STATE_DOZE_SUSPEND); autoBrightnessEnabled = mPowerRequest.useAutoBrightness & (state = Display.STATE_ON | autoBrightnessEnabledInDoze) & brightness 0; mAutomaticBrightnessController.configure(autoBrightnessEnabled, mPowerRequest.screenAutoBrightnessAdjustment, state != Display.STATE_ON); / Apply brightness boost. / We do this here after configuring auto-brightness so that we dont / disable the light sensor during this temporary state. That way when / boost ends we will be able to resume normal auto-brightness behavior / without any delay. if (mPowerRequest.boostScreenBrightness & brightness != PowerManager.BRIGHTNESS_OFF) brightness = PowerManager.BRIGHTNESS_ON; / Apply auto-brightness. boolean slowChange = false; if (brightness = 0) / Use current auto-brightness value and slowly adjust to changes. brightness = clampScreenBrightness(brightness); if (mAppliedAutoBrightness & !autoBrightnessAdjustmentChanged) slowChange = true; / slowly adapt to auto-brightness mAppliedAutoBrightness = true; else mAppliedAutoBrightness = false; else mAppliedAutoBrightness = false; / Use default brightness when dozing unless overridden. if (brightness 0 & (state = Display.STATE_DOZE | state = Display.STATE_DOZE_SUSPEND) brightness = mScreenBrightnessDozeConfig; / Apply manual brightness. / Use the current brightness setting from the request, which is expected / provide a nominal default value for the case where auto-brightness / is not ready yet. if (brightness mScreenBrightnessRangeMinimum) brightness = Math.max(Math.min(brightness - SCREEN_DIM_MINIMUM_REDUCTION, mScreenBrightnessDimConfig), mScreenBrightnessRangeMinimum); if (!mAppliedDimming) slowChange = false; mAppliedDimming = true; / If low power mode is enabled, cut the brightness level by half / as long as it is above the minimum threshold. if (mPowerRequest.lowPowerMode) /低功耗模式 if (brightness mScreenBrightnessRangeMinimum) brightness = Math.max(brightness / 2, mScreenBrightnessRangeMinimum); if (!mAppliedLowPower) slowChange = false; mAppliedLowPower = true; / Animate the screen brightness when the screen is on or dozing. / Skip the animation when the screen is off or suspended. if (!mPendingScreenOff) if (state = Display.STATE_ON | state = Display.STATE_DOZE) animateScreenBrightness(brightness, slowChange ? BRIGHTNESS_RAMP_RATE_SLOW : BRIGHTNESS_RAMP_RATE_FAST); else animateScreenBrightness(brightness, 0); / Determine whether the display is ready for use in the newly requested state. / Note that we do not wait for the brightness ramp animation to complete before / reporting the display is ready because we only need to ensure the screen is in the / right power state even as it continues to converge on the desired brightness. final boolean ready = mPendingScreenOnUnblocker = null & !mColorFadeOnAnimator.isStarted() & !mColorFadeOffAnimator.isStarted() & mPowerState.waitUntilClean(mCleanListener); final boolean finished = ready & !mScreenBrightnessRampAnimator.isAnimating(); / Grab a wake lock if we have unfinished business. if (!finished & !mUnfinishedBusiness) if (DEBUG) Slog.d(TAG, Unfinished business.); mCallbacks.acquireSuspendBlocker();/回调持cpu锁 mUnfinishedBusiness = true;/使用该变量，只能进一次该函数 / Notify the power manager when ready. if (ready & mustNotify) / Send state change. synchronized (mLock) if (!mPendingRequestChangedLocked) mDisplayReadyLocked = true; if (DEBUG) Slog.d(TAG, Display ready!); sendOnStateChangedWithWakelock();/重新在PowerManagerService中调用updatePowerState函数 / Release the wake lock when we have no unfinished business. if (finished & mUnfinishedBusiness) if (DEBUG) Slog.d(TAG, Finished business.); mUnfinishedBusiness = false; mCallbacks.releaseSuspendBlocke