android6.0power显示(亮度等)深入分析(二)DisplayManagerService难点.doc

android6.0 power显示(亮度等)深入分析(二)DisplayManagerService一、DisplayManagerService注册localDisplay的适配层我们先来看构造函数：cpp view plain copy 在CODE上查看代码片派生到我的代码片public DisplayManagerService(Context context) super(context); mContext = context; mHandler = new DisplayManagerHandler(DisplayThread.get().getLooper();/消息处理 mUiHandler = UiThread.getHandler(); mDisplayAdapterListener = new DisplayAdapterListener();/display适配层监视器 mSingleDisplayDemoMode = SystemProperties.getBoolean(persist.demo.singledisplay, false); PowerManager pm = (PowerManager) mContext.getSystemService(Context.POWER_SERVICE); mGlobalDisplayBrightness = pm.getDefaultScreenBrightnessSetting();/成员变量屏幕亮度 我们再来看onStart函数，publish了一个BinderService和LocalService，还有发送了一个消息。cpp view plain copy 在CODE上查看代码片派生到我的代码片Override public void onStart() mHandler.sendEmptyMessage(MSG_REGISTER_DEFAULT_DISPLAY_ADAPTER); publishBinderService(Context.DISPLAY_SERVICE, new BinderService(), true /*allowIsolated*/); publishLocalService(DisplayManagerInternal.class, new LocalService(); 我们看消息处理，就是调用了registerDefaultDisplayAdapter函数：cpp view plain copy 在CODE上查看代码片派生到我的代码片Override public void handleMessage(Message msg) switch (msg.what) case MSG_REGISTER_DEFAULT_DISPLAY_ADAPTER: registerDefaultDisplayAdapter(); break; registerDefaultDisplayAdapter函数cpp view plain copy 在CODE上查看代码片派生到我的代码片private void registerDefaultDisplayAdapter() / Register default display adapter. synchronized (mSyncRoot) registerDisplayAdapterLocked(new LocalDisplayAdapter( mSyncRoot, mContext, mHandler, mDisplayAdapterListener); 再来看看registerDisplayAdapterLockedcpp view plain copy 在CODE上查看代码片派生到我的代码片private void registerDisplayAdapterLocked(DisplayAdapter adapter) mDisplayAdapters.add(adapter); adapter.registerLocked(); 这里就是register了DefaultDisplay的适配层，就是和背光相关的。在新建LocalDisplayAdapter的时候我们把mDisplayAdapterListener传过去了。二、LocalDisplayAdapter & LocalDisplayDeviceLocalDisplayAdapter构造函数调用了父类的，而父类也就是保存了变量cpp view plain copy 在CODE上查看代码片派生到我的代码片public LocalDisplayAdapter(DisplayManagerService.SyncRoot syncRoot, Context context, Handler handler, Listener listener) super(syncRoot, context, handler, listener, TAG); 上面又紧跟着调用了registerLocked函数cpp view plain copy 在CODE上查看代码片派生到我的代码片public void registerLocked() super.registerLocked(); mHotplugReceiver = new HotplugDisplayEventReceiver(getHandler().getLooper(); for (int builtInDisplayId : BUILT_IN_DISPLAY_IDS_TO_SCAN) tryConnectDisplayLocked(builtInDisplayId); tryConnectDisplayLocked函数，先是看传入的builtInDisplayId是否支持，一个是main，一个是hdmi的。cpp view plain copy 在CODE上查看代码片派生到我的代码片private void tryConnectDisplayLocked(int builtInDisplayId) IBinder displayToken = SurfaceControl.getBuiltInDisplay(builtInDisplayId); if (displayToken != null) SurfaceControl.PhysicalDisplayInfo configs = SurfaceControl.getDisplayConfigs(displayToken); if (configs = null) / There are no valid configs for this device, so we cant use it Slog.w(TAG, No valid configs found for display device + builtInDisplayId); return; int activeConfig = SurfaceControl.getActiveConfig(displayToken); if (activeConfig 0) / There is no active config, and for now we dont have the / policy to set one. Slog.w(TAG, No active config found for display device + builtInDisplayId); return; LocalDisplayDevice device = mDevices.get(builtInDisplayId); if (device = null) / Display was added. device = new LocalDisplayDevice(displayToken, builtInDisplayId, configs, activeConfig); mDevices.put(builtInDisplayId, device); sendDisplayDeviceEventLocked(device, DISPLAY_DEVICE_EVENT_ADDED); else if (device.updatePhysicalDisplayInfoLocked(configs, activeConfig) / Display properties changed. sendDisplayDeviceEventLocked(device, DISPLAY_DEVICE_EVENT_CHANGED); else / The display is no longer available. Ignore the attempt to add it. / If it was connected but has already been disconnected, well get a / disconnect event that will remove it from mDevices. 然后再去查找这个LocalDisplayDevice，如果是找到了需要更新下configs，没找到需要新建一个LocalDisplayDevice。最后都调用了sendDisplayDeviceEventLocked函数。我们再来看LocalDisplayDevice，如果传入的是BUILT_IN_DISPLAY_ID_MAIN就是背光的，我们获取背光的Light，保存在mBackLight变量。cpp view plain copy 在CODE上查看代码片派生到我的代码片public LocalDisplayDevice(IBinder displayToken, int builtInDisplayId, SurfaceControl.PhysicalDisplayInfo physicalDisplayInfos, int activeDisplayInfo) super(LocalDisplayAdapter.this, displayToken, UNIQUE_ID_PREFIX + builtInDisplayId); mBuiltInDisplayId = builtInDisplayId; updatePhysicalDisplayInfoLocked(physicalDisplayInfos, activeDisplayInfo); if (mBuiltInDisplayId = SurfaceControl.BUILT_IN_DISPLAY_ID_MAIN) LightsManager lights = LocalServices.getService(LightsManager.class); mBacklight = lights.getLight(LightsManager.LIGHT_ID_BACKLIGHT); else mBacklight = null; 然后上面函数调用了sendDisplayDeviceEventLocked函数，就是调用了传入的参数DisplayAdapterListenercpp view plain copy 在CODE上查看代码片派生到我的代码片protected final void sendDisplayDeviceEventLocked( final DisplayDevice device, final int event) mHandler.post(new Runnable() Override public void run() mListener.onDisplayDeviceEvent(device, event); ); 如果是新建就调用了handleDisplayDeviceAdded函数，cpp view plain copy 在CODE上查看代码片派生到我的代码片private final class DisplayAdapterListener implements DisplayAdapter.Listener Override public void onDisplayDeviceEvent(DisplayDevice device, int event) switch (event) case DisplayAdapter.DISPLAY_DEVICE_EVENT_ADDED: handleDisplayDeviceAdded(device); break; case DisplayAdapter.DISPLAY_DEVICE_EVENT_CHANGED: handleDisplayDeviceChanged(device); break; case DisplayAdapter.DISPLAY_DEVICE_EVENT_REMOVED: handleDisplayDeviceRemoved(device); break; Override public void onTraversalRequested() synchronized (mSyncRoot) scheduleTraversalLocked(false); 我们先来看看handleDisplayDeviceAdded，最后将device保存在了mDisplayDevices中。cpp view plain copy 在CODE上查看代码片派生到我的代码片private void handleDisplayDeviceAdded(DisplayDevice device) synchronized (mSyncRoot) handleDisplayDeviceAddedLocked(device); private void handleDisplayDeviceAddedLocked(DisplayDevice device) DisplayDeviceInfo info = device.getDisplayDeviceInfoLocked(); if (mDisplayDevices.contains(device) Slog.w(TAG, Attempted to add already added display device: + info); return; Slog.i(TAG, Display device added: + info); device.mDebugLastLoggedDeviceInfo = info; mDisplayDevices.add(device); addLogicalDisplayLocked(device); Runnable work = updateDisplayStateLocked(device); if (work != null) work.run(); scheduleTraversalLocked(false); 三、设置背光现在我们在上篇博客不是说背光的调制最后是在DisplayManagerService中，是在下面函数的requestGlobalDisplayStateInternal中调用的cpp view plain copy 在CODE上查看代码片派生到我的代码片public void initPowerManagement(final DisplayPowerCallbacks callbacks, Handler handler, SensorManager sensorManager) synchronized (mSyncRoot) DisplayBlanker blanker = new DisplayBlanker() Override public void requestDisplayState(int state, int brightness) / The order of operations is important for legacy reasons. if (state = Display.STATE_OFF) requestGlobalDisplayStateInternal(state, brightness); callbacks.onDisplayStateChange(state); if (state != Display.STATE_OFF) requestGlobalDisplayStateInternal(state, brightness); ; mDisplayPowerController = new DisplayPowerController( mContext, callbacks, handler, sensorManager, blanker); 我们再来看看requestGlobalDisplayStateInternal函数：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) brightness = PowerManager.BRIGHTNESS_OFF; else if (brightness PowerManager.BRIGHTNESS_ON) brightness = PowerManager.BRIGHTNESS_ON; synchronized (mTempDisplayStateWorkQueue) try / Update the display state within the lock. / Note that we do not need to schedule traversals here although it / may happen as a side-effect of displays changing state. synchronized (mSyncRoot) if (mGlobalDisplayState = state & mGlobalDisplayBrightness = brightness) return; / no change Trace.traceBegin(Trace.TRACE_TAG_POWER, requestGlobalDisplayState( + Display.stateToString(state) + , brightness= + brightness + ); mGlobalDisplayState = 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 avoid blocking other / threads for a long time. for (int i = 0; i mTempDisplayStateWorkQueue.size(); i+) mTempDisplayStateWorkQueue.get(i).run(); Trace.traceEnd(Trace.TRACE_TAG_POWER); finally mTempDisplayStateWorkQueue.clear(); 再看看applyGlobalDisplayStateLocked函数，最后遍历device调用updateDisplayStateLocked函数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 = updateDisplayStateLocked(device); if (runnable != null) workQueue.add(runnable); updateDisplayStateLocked函数调用device的requestDisplayStateLocked返回是Runnable，最后放在workQueue队列中cpp view plain copy 在CODE上查看代码片派生到我的代码片private Runnable updateDisplayStateLocked(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) return device.requestDisplayStateLocked(mGlobalDisplayState, mGlobalDisplayBrightness); return null; 我们再来看看LocalDisplayDevice的requestDisplayStateLocked函数cpp view plain copy 在CODE上查看代码片派生到我的代码片public Runnable requestDisplayStateLocked(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 != brightness) & mBacklight != null; if (stateChanged | brightnessChanged) final int displayId = mBuiltInDisplayId; final IBinder token = getDisplayTokenLocked(); final int oldState = mState; if (stateChanged) mState = state;/ 状态 updateDeviceInfoLocked(); if (brightnessChanged) mBrightness = brightness;/保存亮度 / 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() Override public void run() / Exit a suspended state before making any changes. int currentState = oldState; if (Display.isSuspendedState(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; else return; / old state and new state is off / Apply brightness changes given that we are in a non-suspended state. if (brightnessChanged) setDisplayBrightness(brightness);/设置亮度 / 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) + ); Trace.traceBegin(Trace.TRACE_TAG_POWER, setDisplayState( + id= + displayId + , state= + Display.stateToString(state) + ); try final int mode = getPowerModeForState(state); SurfaceControl.setDisplayPowerMode(token, mode); finally Trace.traceEnd(Trace.TRACE_TAG_POWER); private void setDisplayBrightness(int brightness) if (DEBUG) Slog.d(TAG, setDisplayBrightness( + id= + displayId + , brightness= + brightness + ); Trace.traceBegin(Trace.TRACE_TAG_POWER, setDisplayBrightness( + id= + displayId + , brightness= + brightness + ); try mBacklight.setBrightness(brightness);/真正的设置背光 finally Trace.traceEnd(Trace.TRACE_TAG_POWER); ; return null; 上面函数返回一个Runnable放在workQueue，在Runnable 中会调用mBacklight.setBrightness设置背光。之前是将Runnable接口都放在了mTempDisplayStateWorkQueue中，然后遍历调用了run函数。最后就调用到了LocalDisplayDevice的Runnable接口中设置背光了。cpp view plain copy 在CODE上查看代码片派生到我的代码片synchronized (mSyncRoot) if (mGlobalDisplayState = state & mGlobalDisplayBrightness = brightness) return; / no change Trace.traceBegin(Trace.TRACE_TAG_POWER, requestGlobalDisplayState( + Display.stateToString(state) + , brightness= + brightness + ); mGlobalDisplayState = 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 avoid blocking other / threads for a long time. for (int i = 0; i mTempDisplayStateWorkQueue.size(); i+) mTempDisplayStateWorkQueue.get(i).run(); 四、背光hal层我们先来看看LightsServicecpp view plain copy 在CODE上查看代码片派生到我的代码片public class LightsService extends SystemService static final String TAG = LightsService; static final boolean DEBUG = false; final LightImpl mLights = new LightImplLightsManager.LIGHT_ID_COUNT; private final class LightImpl extends Light private LightImpl(int id) mId = id; Override public void setBrightness(int brightness) setBrightness(bri