and5.1PowerManagerService深入分析(三)updatePowerStateLocked函数

and5.1PowerManagerService

深入分析

（三）

updatePowerStateLocked

函数

PMS

更新各个状态 ，最终都会调用

updatePowerStateLocked

函数，下面我们来分析下

[java] view plain copy

private void updatePowerStateLocked() {

if (!mSystemReady || mDirty == 0) {//mD irty=0

代表没有变化，或者系统没有准备好，直

接退出< /p>

return;

}

if (!ock(mLock)) {

(TAG

,

manager

lock

was

not

held

when

calling

updatePowerStateLocked

}

egin(_TAG_POWER,

try {

// Phase 0: Basic state updates.

upd ateIsPoweredLocked(mDirty);//

更新电源状态

updateStayOnLocked(mDirty);

updateScreenBrightnessBoost Locked(mDirty);

updateIsPoweredLocked

函数，先是要

dirty

有

DIRTY_BA

TTE RY_STATE

标志位。我们在下

面分析下，什么时候会有这 个标志位

[java] view plain copy

private void updateIsPoweredLocked(int dirty) {

if ((dirty & DIRTY_BA

TTERY_STATE) != 0) {

final boolean wasPowered = mIsPowered;

final int oldPlugType = mPlugType;

final boolean oldLevelLow = mBatteryLevelLow;

mIsPowered

=

red(Y_PLUGGED_ANY);//

这些都是

从

BatteryService

获取

mPlugType = gType();

mBatteryLevel = teryLevel();

mBatteryLevelLow = teryLevelLow();

if (DEBUG_SPEW) {

Slog.d(TAG

,

+

+

+

+

}

if (wasPowered != mIsPowered || oldPlugType != mPlugType) {//

是否充电或者充电类

型改变了

mDirty |= DIRTY_IS_POWERED;//mDirty

置位

// Update wireless dock detection state.

final

boolean

dockedOnWirelessCharger

=

(//

无

线充电相关

mIsPowered, mPlugType, mBatteryLevel);

// Treat plugging and unplugging the devices as a user activity.

// Users find it disconcerting when they plug or unplug the device

// and it shuts off right away.

// Some devices also wake the device when plugged or unplugged because

// they don't have a charging LED.

final long now = Millis();

if (shouldWakeU pWhenPluggedOrUnpluggedLocked(wasPowered, oldPlugType,

dockedOnWirelessCharger)) {//

是否需要唤醒设备

wakeUpNoUpdateLocked(now, _UID);

}

userActivityNoU pdateLocked(//

触发

userActivity

now,

_ACTIVITY_EVENT_OTHER,

0,

_UID);

// Tell the notifier whether wireless charging has started so that

// it can provide feedback to the user.

if (dockedOnWirelessCharger) {//

无线充电相关

lessChargingStarted();

}

}

if (wasPowered != mIsPowered || oldLevelLow != mBatteryLevelLow) {

if (oldLevelLow != mBatteryLevelLow && !mBatteryLevelLow) {

if (DEBUG_SPEW) {

Slog.d(TAG,

}

mAutoLowPowerModeSnoozing = false;

}

updateLowPowerModeLocked(); //

更新低功耗模式

}

}

}

首

先

systemReady

函

数

最

终

会

把

< br>mDirty

置

位

为

，

还< /p>

有

收

BatterySevice

发出来的广播，最总也会置这个标志位。

[java] view plain copy

private final class BatteryReceiver extends BroadcastReceiver {

@Override

public void onReceive(Context context, Intent intent) {

synchronized (mLock) {

handleBatteryStateChangedLocked();

}

}

}

[java] view plain copy

private void handleBatteryStateChangedLocked() {

mDirty |= DIRTY_BATTERY_STA

TE;

updatePowerStateLocked();

}

再来看看电池状态发生什么变化要唤醒设备：

[java] view plain copy

private boolean shouldWakeUpWhenPluggedOrUnpluggedLocked(

boolean wasPowered, int oldPlugType, boolean dockedOnWirelessCharger) {

// Don't wake when powered unless configured to do so.

if (!mWakeUpWhenPluggedOrUnpluggedConfig) {//

< br>如果资源中没有配置这项，直接退出

不唤醒设备

return false;

}

// Don't wake when undocked from wireless charger.

// See WirelessChargerDetector for justification.

if (wasPowered && !mIsPowered

&&

oldPlugType

==

TTERY_PLUGGED_WIRELESS)

{//

这

是一个

拔出的工作，然后之前的无线充电

return false;

}

// Don't wake when docked on wireless charger unless we are certain of it.

// See WirelessChargerDetector for justification.

if (!wasPowered && mIsPowered

&& mPlugType ==

TTERY_PLUGGE D_WIRELESS//

插入动

作，现在是无线充电

&& !dockedOnWirelessCharger) {

return false;

}

// If already dreaming and becoming powered, then don't wake.

if (mIsPowered && mWakefulness == W

AKEFULNESS_DREAMING) {//

正在充电，但是

mWakefulness

是做梦状态

return false;

}

// Don't wake while theater mode is enabled.

if (mTheaterModeEnabled && !mWakeUpWhenPluggedOrUnpluggedInTheaterModeConfig)

{

return false;

}

// Otherwise wake up!

return true;//

其他就唤醒设备

}

继续分析

updatePowerS tateLocked

函数，分析

updateStayOnL ocked

函数。一般这个函数

mStatyon

为

fasle

，除非在资源中设置哪种充电状态下可 以长亮。

[java] view plain copy

private void updateStayOnLocked(int dirty) {

if ((dirty & (DIRTY_BATTERY_STA

TE | DIRTY_SETTINGS)) != 0) {//

当

d irty

是电池状

态和设置的状态改变时

final boolean wasStayOn = mStayOn;

if (mStayOnWhilePluggedInSetting != 0//

这个值从资源中读取，

一般设置的话代表哪

种充电时可以常亮

&&

!isMaximumScreenOffTimeou tFromDeviceAdminEnforcedLocked())

{//

看有没有设

mMaximumScreenOffTimeoutF romDeviceAdmin

屏幕最大亮屏时间，没设默认最

大。那么这个函数返回是

false

mStayOn

=

red(mStayOnWhilePluggedInSetting);

} else {

mStayOn = false;

}

if (mStayOn != wasStayOn) {

mDirty |= DIRTY_STAY_ON;

}

}

}

继续分析

updatePowerS tateLocked

函数的

updateScreenBri ghtnessBoostLocked

函数，这个函

数是更新 屏幕是否保持最亮状态

[java] view plain copy

private void updateScreenBrightnessBoostLocked(int dirty) {

if

((dirty

&

DIRTY_SCREEN_BRIGHTNESS_BOOST)

!=

0)

{//

< br>这

个

状

态

实

在

boostScreenBrightnessInte rnal

函

数

中

设

置

最

亮

时

置

位

，

当

然

下

面

发