Android源码笔记--电量

Posted 2023-03-13 ljt2724960661

            这一节主要了解电源更新，源码中一般是通过xxxLocked来实现。函数updatePowerStateLocked 的功能是更新电源状态的锁定，通过把影响到 PowerManagement 发生变化的放在一起进行更新，函数updatePowerStateLocked的具体实现代码如下所示：

/frameworks/base/services/core/java/com/android/server/power/PowerManagerService.java
   
   private void updatePowerStateLocked() 
        if (!mSystemReady || mDirty == 0) 
            return;
        
        if (!Thread.holdsLock(mLock)) 
            Slog.wtf(TAG, "Power manager lock was not held when calling updatePowerStateLocked");
        

        Trace.traceBegin(Trace.TRACE_TAG_POWER, "updatePowerState");
        try 
            // Phase 0: Basic state updates.
            updateIsPoweredLocked(mDirty);
            updateStayOnLocked(mDirty);
            updateScreenBrightnessBoostLocked(mDirty);

            // Phase 1: Update wakefulness.
            // Loop because the wake lock and user activity computations are influ