PowerManagerService

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电源管理架构

• 应用接口层

初始化

SystemServer.java
SystemServer启动PowerManagerService服务

/**
 * Starts the small tangle of critical services that are needed to get
 * the system off the ground.  These services have complex mutual dependencies
 * which is why we initialize them all in one place here.  Unless your service
 * is also entwined in these dependencies, it should be initialized in one of
 * the other functions.
 */
private void startBootstrapServices() { 
  ...

    // Power manager needs to be started early because other services need it.
    // Native daemons may be watching for it to be registered so it must be ready
    // to handle incoming binder calls immediately (including being able to verify
    // the permissions for those calls).
    traceBeginAndSlog("StartPowerManager");
    mPowerManagerService = mSystemServiceManager.startService(PowerManagerService.class);
    traceEnd();
  ...
}

构造函数

frameworks/base/services/core/java/com/android/server/power/PowerManagerService.java

public final class PowerManagerService extends SystemService
        implements Watchdog.Monitor {
    private static final String TAG = "PowerManagerService";
    ...
    public PowerManagerService(Context context) {
        super(context);
        mContext = context;
        mHandlerThread = new ServiceThread(TAG,
                Process.THREAD_PRIORITY_DISPLAY, false /*allowIo*/);
        mHandlerThread.start();
        mHandler = new PowerManagerHandler(mHandlerThread.getLooper());
        mConstants = new Constants(mHandler);
        mAmbientDisplayConfiguration = new AmbientDisplayConfiguration(mContext);

        mBatterySavingStats = new BatterySavingStats(mLock);
        mBatterySaverPolicy = new BatterySaverPolicy(mLock, mContext, mBatterySavingStats);
        mBatterySaverController = new BatterySaverController(mLock, mContext,
                BackgroundThread.get().getLooper(), mBatterySaverPolicy, mBatterySavingStats);
        mBatterySaverStateMachine = new BatterySaverStateMachine(
                mLock, mContext, mBatterySaverController);

        synchronized (mLock) {
            mWakeLockSuspendBlocker = createSuspendBlockerLocked("PowerManagerService.WakeLocks");
            mDisplaySuspendBlocker = createSuspendBlockerLocked("PowerManagerService.Display");
            mDisplaySuspendBlocker.acquire();
            mHoldingDisplaySuspendBlocker = true;
            mHalAutoSuspendModeEnabled = false;
            mHalInteractiveModeEnabled = true;

            mWakefulness = WAKEFULNESS_AWAKE;

            sQuiescent = SystemProperties.get(SYSTEM_PROPERTY_QUIESCENT, "0").equals("1");

            nativeInit();
            nativeSetAutoSuspend(false);
            nativeSetInteractive(true);
            nativeSetFeature(POWER_FEATURE_DOUBLE_TAP_TO_WAKE, 0);
        }
    }
}

onStart()中发布BinderService，LocalService。分别供其他进程，进程内其他服务调用，并将PowerManagerService加入到watchdog监控中。

    @Override
    public void onStart() {
        publishBinderService(Context.POWER_SERVICE, new BinderService());
        publishLocalService(PowerManagerInternal.class, new LocalService());

        Watchdog.getInstance().addMonitor(this);
        Watchdog.getInstance().addThread(mHandler);
    }

    private final class BinderService extends IPowerManager.Stub {
      ...
    }


    private final class LocalService extends PowerManagerInternal {
      ...
    }

PowerManagerService（一）— 初始化