定制网站系统,模板网站好还是自助建站好,怎么做网站讯息,建设网站站点过程中Android Framework系列—CarPower深度睡眠
之前博客说了CarPower的开机启动流程 这里分析一下#xff0c;Android CarPower实现深度睡眠的流程。 首先#xff0c;什么是深度睡眠(Deep Sleep)?
Android进入Deep Sleep后#xff0c;关闭屏幕、关闭CPU的电源#xff0c;保持…Android Framework系列—CarPower深度睡眠
之前博客说了CarPower的开机启动流程 这里分析一下Android CarPower实现深度睡眠的流程。 首先什么是深度睡眠(Deep Sleep)?
Android进入Deep Sleep后关闭屏幕、关闭CPU的电源保持RAM的电源激活状态。深度睡眠会进行Suspend-to-RAM挂起到内存做车载的经常会听到的STR。当然深度睡眠还一种是挂起到硬盘Suspend-to-Disk不过目前主要用的是STR。所以STR是深度睡眠时的状态但STR不等于深度睡眠。
DeepSleep或STR需要内核配合实现。通过这种技术车载系统可以进入低能耗模式同时又可以再用户需要时实现快速(非常快因为从内存中恢复状态的启动。 感觉这种方式跟snapshot快启动有点类似。不过是两个概念上的事情了。
下面摘自Android官网对这种状态的介绍。 也称为“挂起到 RAM”S2R 或 STR。将 SoC 置于 S3 电源模式CPU 断电而 RAM 仍通电。 VMCU 应将 SoC 置于“深度睡眠”状态并断开应用处理器的电源。然后AAOS 将进入“挂起到 RAM”状态但不执行任何代码。 整套深度睡眠的实现涉及的主要模块这里指单Android系统。当前还有Qnx之类的hypervisor
MCU/VMCU控制电源发送电源状态给SOCAndroidVehicle HAL一般由硬件供应商实现与MCU通信can、以太方式CarPowerManagerService(CPMS): 实现Android侧的电源控制应用电源策略。CarPowerManager(CPM): CPMS的客户端通知电源状态给应用等待应用回复状态等。
下面是摘自Android官网的深入睡眠流程描述 只有 VMCU 可以启动深度睡眠。启动深度睡眠后VMCU 会通过 VHAL 向 CPMS 发送通知。CPMS 通过使用由 CPM 提供的新状态 ID 调用 onStateChanged() 方法将状态更改为“关闭准备”并向所有观察者监控 CPMS 的应用和服务广播此状态转换。 CPM 在应用/服务与 CPMS 之间进行协调。在 CPM 的 onStateChanged() 方法中同步调用应用/服务的 onStateChanged() 方法。大多数应用和服务需要完成其准备后才能从该调用返回。特权服务可以在为 PRE_SHUTDOWN_PREPARE、SUSPEND_ENTER 和 POST_SUSPEND_ENTER 返回后异步继续关闭准备。在此情况下特权服务应在完成准备时对提供的 CompletablePowerStateChangeFuture 对象调用 complete()。请注意SHUTDOWN_PREPARE 不允许异步准备。在向 VHAL 发送 DEEP_SLEEP_ENTRY 之前CPMS 会定期向 VHAL 发送推迟关闭的请求。 当所有 CPM 对象完成关闭准备后CPMS 会向 VHAL 发送 AP_POWER_STATE_REPORTVHAL 随后通知 VMCU告知它 AP 已准备好挂起。CPMS 还会调用其挂起方法以挂起内核。 下面的图是Android官网对于深度睡眠的时序图。这里贴在这里。后面会根据源码分析并画一个跟代码对应的时序图。
CPMS深度睡眠代码实现
到这里我们开始分析CPMS的实现。代码基于Android11
首先VMCU请求挂起。Vehicle HAL Hal层的nativeservice发送“AP_POWER_STATE_REQ(SHUTDOWN_PREPARE)” 这样CarService中的 VehicleHalClient端 就收到了这个通知。一路通知给CPMS进行状态处理。
packages/services/Car/service/src/com/android/car/hal/VehicleHal.java
public void onPropertyEvent(ArrayListVehiclePropValue propValues) {// 省略for (HalServiceBase s : mServicesToDispatch) {// 通知给监听者s.onHalEvents(s.getDispatchList());s.getDispatchList().clear();}mServicesToDispatch.clear();
}packages/services/Car/service/src/com/android/car/hal/PowerHalService.java
Override
public void onHalEvents(ListVehiclePropValue values) {// 省略dispatchEvents(values, listener);
}private void dispatchEvents(ListVehiclePropValue values, PowerEventListener listener) {for (VehiclePropValue v : values) {switch (v.prop) {case AP_POWER_STATE_REPORT:// Ignore this property event. It was generated inside of CarService.break;case AP_POWER_STATE_REQ:int state v.value.int32Values.get(VehicleApPowerStateReqIndex.STATE);int param v.value.int32Values.get(VehicleApPowerStateReqIndex.ADDITIONAL);Log.i(CarLog.TAG_POWER, Received AP_POWER_STATE_REQ powerStateReqName(state) param param);// 通知状态给CPMS对象// AP_POWER_STATE_REQ(SHUTDOWN_PREPARE, CAN_SLEEP)listener.onApPowerStateChange(new PowerState(state, param));break;case DISPLAY_BRIGHTNESS:{// 省略}break;}}
}packages/services/Car/service/src/com/android/car/CarPowerManagementService.java
Override
public void onApPowerStateChange(PowerState state) {synchronized (mLock) {mPendingPowerStates.addFirst(new CpmsState(state));mLock.notify();}mHandler.handlePowerStateChange();
}private void handlePowerStateChange() {Message msg obtainMessage(MSG_POWER_STATE_CHANGE);sendMessage(msg);
}Override
public void handleMessage(Message msg) {CarPowerManagementService service mService.get();if (service null) {Slog.i(TAG, handleMessage null service);return;}switch (msg.what) {case MSG_POWER_STATE_CHANGE:// 开始处理// service是doHandlePowerStateChange对象service.doHandlePowerStateChange();break;// 省略}
}private void doHandlePowerStateChange() {// 省略了mCurrentState state;switch (state.mState) {case CpmsState.WAIT_FOR_VHAL:handleWaitForVhal(state);break;case CpmsState.ON:handleOn();break;case CpmsState.SHUTDOWN_PREPARE:// 处理SHUTDOWN_PREPAREhandleShutdownPrepare(state);break;// 省略default:// Illegal state// TODO: Throw exception?break;}
}CarPowerManagementService开始处理SHUTDOWN_PREPARE。主要是关闭VR交互、关闭屏幕。通知状态给CPMS的客户端启动超时等待客户端处理完成使用****CarPowerStateListenerWithCompletion的客户端
packages/services/Car/service/src/com/android/car/CarPowerManagementService.java
private void handleShutdownPrepare(CpmsState newState) {setVoiceInteractionDisabled(true);mSystemInterface.setDisplayState(false);// Shutdown on finish if the system doesnt support deep sleep or doesnt allow it.// 通知状态给客户端sendPowerManagerEvent(CarPowerStateListener.SHUTDOWN_PREPARE);mHal.sendShutdownPrepare();doHandlePreprocessing();
}private void doHandlePreprocessing() {int intervalMs;int pollingCount;synchronized (mLock) {intervalMs mShutdownPollingIntervalMs;pollingCount (mShutdownPrepareTimeMs / mShutdownPollingIntervalMs) 1;}if (Build.IS_USERDEBUG || Build.IS_ENG) {// 这里省略了主要是可以通过属性修改超时时间。}Slog.i(TAG, processing before shutdown expected for: mShutdownPrepareTimeMs ms, adding polling: pollingCount);// 启动超时任务定期检查。那些使用 CarPowerStateListenerWithCompletion//带有future告知CPMS自己是否处理完了的应用端是否处理完毕。// 如果超时还没完成强制走DeepSleep流程。synchronized (mLock) {mProcessingStartTime SystemClock.elapsedRealtime();releaseTimerLocked();mTimer new Timer();mTimerActive true;mTimer.scheduleAtFixedRate(new ShutdownProcessingTimerTask(pollingCount),0 /*delay*/,intervalMs);}if (mSwitchGuestUserBeforeSleep) {switchToNewGuestIfNecessary();}
}// 超时处理Task
private class ShutdownProcessingTimerTask extends TimerTask {private final int mExpirationCount;private int mCurrentCount;private ShutdownProcessingTimerTask(int expirationCount) {mExpirationCount expirationCount;mCurrentCount 0;}Overridepublic void run() {synchronized (mLock) {if (!mTimerActive) {// Ignore timer expiration since we got cancelledreturn;}mCurrentCount;if (mCurrentCount mExpirationCount) {// 超时处理。给Vehicle HAL通知DEEP_SLEEP_ENTRY告知可以开始进入深入睡眠状态。PowerHandler handler;releaseTimerLocked();handler mHandler;handler.handleProcessingComplete();} else {// 定期通过PowerServiceHAL向Vehicle HAL发送延时通知。mHal.sendShutdownPostpone(SHUTDOWN_EXTEND_MAX_MS);}}}
}这里假设走正常的处理了即所有客户端CarPowerStateListenerWithCompletion期限内完成了处理。那么CPMS就会通过PowerserviceHAL告知 VehicleHAL “DEEP_SLEEP_ENTRY”状态。下面是CarPowerStateListenerWithCompletion的一个例子。
mCarPowerManager.setListenerWithCompletion(mCarPowerStateListener);
private final CarPowerStateListenerWithCompletion mCarPowerStateListener new CarPowerStateListenerWithCompletion() {Overridepublic void onStateChanged(int state, CompletableFutureVoid future) {if (state CarPowerManager.CarPowerStateListener.SHUTDOWN_PREPARE) {// 例子应用端处理完成后调用future.complete 告知CPMS处理完成if (future ! null) {future.complete(null);}}}
};
packages/services/Car/service/src/com/android/car/CarPowerManagementService.java
// future.complete 会触发CPMS这个函数。
Override
public void finished(ICarPowerStateListener listener) {ICarImpl.assertPermission(mContext, Car.PERMISSION_CAR_POWER);ICarImpl.assertCallingFromSystemProcessOrSelf();finishedImpl(listener.asBinder());
}private void finishedImpl(IBinder binder) {boolean allAreComplete;synchronized (mLock) {mListenersWeAreWaitingFor.remove(binder);allAreComplete mListenersWeAreWaitingFor.isEmpty();}// 所有Listener处理完成了。if (allAreComplete) {signalComplete();}
}private void signalComplete() {if (mCurrentState.mState CpmsState.SHUTDOWN_PREPARE|| mCurrentState.mState CpmsState.SIMULATE_SLEEP) {PowerHandler powerHandler;// All apps are ready to shutdown/suspend.synchronized (mLock) {if (!mShutdownOnFinish) {if (mLastSleepEntryTime mProcessingStartTime mLastSleepEntryTime SystemClock.elapsedRealtime()) {Slog.i(TAG, signalComplete: Already slept!);return;}}powerHandler mHandler;}Slog.i(TAG, Apps are finished, call handleProcessingComplete());powerHandler.handleProcessingComplete();}
}private void handleProcessingComplete() {removeMessages(MSG_PROCESSING_COMPLETE);Message msg obtainMessage(MSG_PROCESSING_COMPLETE);sendMessage(msg);
}Override
public void handleMessage(Message msg) {CarPowerManagementService service mService.get();if (service null) {Slog.i(TAG, handleMessage null service);return;}switch (msg.what) {case MSG_POWER_STATE_CHANGE:service.doHandlePowerStateChange();break;case MSG_DISPLAY_BRIGHTNESS_CHANGE:service.doHandleDisplayBrightnessChange(msg.arg1);break;case MSG_MAIN_DISPLAY_STATE_CHANGE:service.doHandleMainDisplayStateChange((Boolean) msg.obj);break;case MSG_PROCESSING_COMPLETE:// 走这里service.doHandleProcessingComplete();break;}
}private void doHandleProcessingComplete() {int listenerState;synchronized (mLock) {releaseTimerLocked();if (!mShutdownOnFinish mLastSleepEntryTime mProcessingStartTime) {// entered sleep after processing start. So this could be duplicate request.Slog.w(TAG, Duplicate sleep entry request, ignore);return;}// 可以设置关机即不进入挂起。// 默认状态走SUSPEND_ENTERlistenerState mShutdownOnFinish? CarPowerStateListener.SHUTDOWN_ENTER : CarPowerStateListener.SUSPEND_ENTER;}// 处理状态变化这个函数是两参的并且是private的onApPowerStateChange(CpmsState.WAIT_FOR_FINISH, listenerState);
}private void onApPowerStateChange(int apState, int carPowerStateListenerState) {CpmsState newState new CpmsState(apState, carPowerStateListenerState);synchronized (mLock) {mPendingPowerStates.addFirst(newState);mLock.notify();}// 用 handler线程处理。下面省略了中间流程最终调用的是doHandlePowerStateChangemHandler.handlePowerStateChange();
}private void doHandlePowerStateChange() {mCurrentState state;switch (state.mState) {// 省略case CpmsState.WAIT_FOR_FINISH:// 走这里handleWaitForFinish(state);break;// 省略default:// Illegal state// TODO: Throw exception?break;}
}private void handleWaitForFinish(CpmsState state) {// 通知给CPMS的监听者当前状态sendPowerManagerEvent(state.mCarPowerStateListenerState);int wakeupSec;synchronized (mLock) {// If were shutting down immediately, dont schedule// a wakeup time.// 可以设置进入休眠状态后的唤醒时间默认是不设置的0表示一直Sleep除非VMCU主动唤起wakeupSec mGarageModeShouldExitImmediately ? 0 : mNextWakeupSec;}switch (state.mCarPowerStateListenerState) {case CarPowerStateListener.SUSPEND_ENTER:// // 给Vehicle HAL发送状态// 发送的是DEEP_SLEEP_ENTRY告知可以进入休眠状态了。mHal.sendSleepEntry(wakeupSec);break;case CarPowerStateListener.SHUTDOWN_ENTER:mHal.sendShutdownStart(wakeupSec);break;}
}到这里就是告诉了VMCUAndroid 挂起Ready了也就是一切准备完成。然后MCU就会发送AP_POWER_STATE_REQ(FINISHED)告知Android侧调用Linux内核的实现把自己挂起来Supend。消息通知流程跟上面的onPropertyEvent一致这部分下面就省略了。
packages/services/Car/service/src/com/android/car/CarPowerManagementService.java
private void doHandlePowerStateChange() {mCurrentState state;switch (state.mState) {// 省略case CpmsState.SUSPEND:// Received FINISH from VHAL// 走这里handleFinish();break;default:// Illegal state// TODO: Throw exception?break;}
}private void handleFinish() {// 省略// 关闭VoicesetVoiceInteractionDisabled(true);// To make Kernel implementation simpler when going into sleep.disableWifi();if (mustShutDown) {// shutdown HUmSystemInterface.shutdown();} else {// 处理深入睡眠doHandleDeepSleep(simulatedMode);}mShutdownOnNextSuspend false;
}private void doHandleDeepSleep(boolean simulatedMode) {// keep holding partial wakelock to prevent entering sleep before enterDeepSleep call// enterDeepSleep should force sleep entry even if wake lock is kept.mSystemInterface.switchToPartialWakeLock();mHandler.cancelProcessingComplete();synchronized (mLock) {mLastSleepEntryTime SystemClock.elapsedRealtime();}int nextListenerState;if (simulatedMode) {// 省略} else {// 最终会调用Kernel接口Supend To RAM感兴趣的小伙伴可以顺着这个接口看下去。// 挂成功的情况下面下面的代码就不会走了CPU都没电了。// 之后的代码就是CPU上电后的恢复流程了。// 可以看出恢复前要刷新一下屏幕亮度。然后走WAIT_FOR_VHAL状态。boolean sleepSucceeded suspendWithRetries();if (!sleepSucceeded) {// Suspend failed and we shut down instead.// We either wont get here at all or we will power off very soon.return;}// We suspended and have now resumednextListenerState CarPowerStateListener.SUSPEND_EXIT;}synchronized (mLock) {mIsResuming true;// Any wakeup time from before is no longer valid.mNextWakeupSec 0;}Slog.i(TAG, Resuming after suspending);mSystemInterface.refreshDisplayBrightness();onApPowerStateChange(CpmsState.WAIT_FOR_VHAL, nextListenerState);
}综上是Android CarPower的深入睡眠睡眠主要流程实际开发过程中。根据业务进行扩展一般会添加一个跟CPMS平行或者基于它的新的电源模块。下面是上面代码的时序图供参考。
