https://blog.csdn.net/Gaugamela/article/details/52838654
Android7.0 PowerManagerService(3) 核心函数updatePowerStateLocked的主要流程
https://mp.weixin.qq.com/s/P3IvBrYt7afEa4XyEd3BQg
PowerManagerService分析(二)
https://blog.csdn.net/u011311586/article/details/51034313
（原创）android6.0系统 PowerManager深入分析
Platform: RK3288
OS: Android 7.1.2
Kernel: 4.4.143
一.frameworks\base\services\core\java\com\android\server\power\PowerManagerService.java
1.在updatePowerStateLocked()方法中，设置了一个死循环，并且上述分析的两个方法都在死循环中执行，
为何设计一个死循环与它循环内部的实现有关系。updateWakefulnessLocked(),这个方法是退出循环的关键。
如果这个方法返回false,则循环结束，如果返回true，则进行下一次循环
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 influenced
// by changes in wakefulness.
final long now = SystemClock.uptimeMillis();
int dirtyPhase2 = 0;
for (;;) {
int dirtyPhase1 = mDirty;
dirtyPhase2 |= dirtyPhase1;
mDirty = 0;
updateWakeLockSummaryLocked(dirtyPhase1);
updateUserActivitySummaryLocked(now, dirtyPhase1);
if (!updateWakefulnessLocked(dirtyPhase1)) {
break;
// Phase 2: Update display power state.
boolean displayBecameReady = updateDisplayPowerStateLocked(dirtyPhase2);
// Phase 3: Update dream state (depends on display ready signal).
updateDreamLocked(dirtyPhase2, displayBecameReady);
// Phase 4: Send notifications, if needed.
finishWakefulnessChangeIfNeededLocked();
// Phase 5: Update suspend blocker.
// Because we might release the last suspend blocker here, we need to make sure
// we finished everything else first!
updateSuspendBlockerLocked();
} finally {
Trace.traceEnd(Trace.TRACE_TAG_POWER);
2.进入休眠,实现休眠的方法
private boolean updateWakefulnessLocked(int dirty) {
boolean changed = false;
if ((dirty & (DIRTY_WAKE_LOCKS | DIRTY_USER_ACTIVITY |
DIRTY_BOOT_COMPLETED
| DIRTY_WAKEFULNESS | DIRTY_STAY_ON |
DIRTY_PROXIMITY_POSITIVE
| DIRTY_DOCK_STATE)) != 0) {
//当前屏幕保持唤醒&&设备将要退出唤醒状态(睡眠or屏保)
if (mWakefulness == WAKEFULNESS_AWAKE && isItBedTimeYetLocked()) {
Slog.d(TAG, "updateWakefulnessLocked: Bed time...");
final long time = SystemClock.uptimeMillis();
//是否在休眠时启用屏保
if (shouldNapAtBedTimeLocked()) {
//进入屏保，返回true
changed = napNoUpdateLocked(time, Process.SYSTEM_UID);
} else {
//进入睡眠，返回true
changed = goToSleepNoUpdateLocked(time,
PowerManager.GO_TO_SLEEP_REASON_TIMEOUT, 0,
Process.SYSTEM_UID);
return changed;
3.updateUserActivitySummaryLocked主要根据用户最后的活动来决定当前屏幕的状态。
举个栗子，休眠的时，先变暗一下(USER_ACTIVITY_SCREEN_DIM 暗屏)，再休眠
在该函数中用mUserActivitySummary变量存储当前屏幕的状态。
一共有3中基本状态：
* USER_ACTIVITY_SCREEN_BRIGHT 点亮屏幕
* USER_ACTIVITY_SCREEN_DIM 屏幕变暗
* USER_ACTIVITY_SCREEN_DREAM 屏保状态
从代码可以看出，屏幕变化和userActivity活动有关，它根据最后的userActivity活动的时间决定点亮屏幕、调暗屏幕或熄灭屏幕
* Updates the value of mUserActivitySummary to summarize the user requested
* state of the system such as whether the screen should be bright or dim.
* Note that user activity is ignored when the system is asleep.
private void updateUserActivitySummaryLocked(long now, int dirty) {
if ((dirty & (DIRTY_WAKE_LOCKS | DIRTY_USER_ACTIVITY
| DIRTY_WAKEFULNESS | DIRTY_SETTINGS)) != 0) {
mHandler.removeMessages(MSG_USER_ACTIVITY_TIMEOUT);
long nextTimeout = 0;
if (mWakefulness == WAKEFULNESS_AWAKE
|| mWakefulness == WAKEFULNESS_DREAMING
|| mWakefulness == WAKEFULNESS_DOZING) {
//获取进入休眠状态的时间sleepTimeout
//getSleepTimeoutLocked中会判断休眠时间和屏幕熄灭时间的关系
//如果休眠时间sleepTimeout小于屏幕熄灭时间screenOfftime，
//则休眠时间被调整为屏幕熄灭时间，因为屏幕亮屏状态下，终端不能进入休眠
final int sleepTimeout = getSleepTimeoutLocked();
//获取屏幕熄灭的时间
final int screenOffTimeout = getScreenOffTimeoutLocked(sleepTimeout);
//获取屏幕变暗的时间
final int screenDimDuration = getScreenDimDurationLocked(screenOffTimeout);
//当Window Manager判定用户inactive时，将此标志置为true
final boolean userInactiveOverride = mUserInactiveOverrideFromWindowManager;
//类似于之前的mWakeLockSummary，将当前的用户事件，转化为PMS可以处理的屏幕状态
mUserActivitySummary = 0;
//在唤醒的状态下，发生过用户事件
if (mLastUserActivityTime >= mLastWakeTime) {
//重新计算出屏幕需要变暗的时间
nextTimeout = mLastUserActivityTime
+ screenOffTimeout - screenDimDuration;
if (now < nextTimeout) {
//如果没有到达需要变暗的时间，那么当前屏幕的状态为USER_ACTIVITY_SCREEN_BRIGHT(亮屏)
mUserActivitySummary = USER_ACTIVITY_SCREEN_BRIGHT;
} else {
//到达变暗的时间，则计算出屏幕熄灭的时间
nextTimeout = mLastUserActivityTime + screenOffTimeout;
if (now < nextTimeout) {
//还没到熄灭的时间，则当前屏幕的状态为USER_ACTIVITY_SCREEN_DIM(暗屏)
mUserActivitySummary = USER_ACTIVITY_SCREEN_DIM;
//注意mUserActivitySummary为0才会进入下面的分支
//即上面改变mUserActivitySummary的条件不满足时，才会进入这个分支（例如：唤醒状态下，没发生过改变屏幕状态的UserActivity）
if (mUserActivitySummary == 0
//mLastUserActivityTimeNoChangeLights表示用户最后的活动不会改变屏幕当前的状态
&& mLastUserActivityTimeNoChangeLights >= mLastWakeTime) {
//计算下次屏幕熄灭的时间
nextTimeout = mLastUserActivityTimeNoChangeLights + screenOffTimeout;
//还未到达熄屏时间
if (now < nextTimeout) {
if (mDisplayPowerRequest.policy == DisplayPowerRequest.POLICY_BRIGHT) {
//当前屏幕是亮屏，仍然设置为亮屏
mUserActivitySummary = USER_ACTIVITY_SCREEN_BRIGHT;
} else if (mDisplayPowerRequest.policy == DisplayPowerRequest.POLICY_DIM) {
//当前屏幕是变暗，仍然设置为变暗
mUserActivitySummary = USER_ACTIVITY_SCREEN_DIM;
if (mUserActivitySummary == 0) {
//若定义了有效的休眠时间
if (sleepTimeout >= 0) {
//计算用户最后的活动时间
final long anyUserActivity = Math.max(mLastUserActivityTime,
mLastUserActivityTimeNoChangeLights);
//只有在唤醒状态下，进行了用户活动，才会重新更新休眠时间 (此时，应该是有过用户活动，但过了息屏时间了)
if (anyUserActivity >= mLastWakeTime) {
nextTimeout = anyUserActivity + sleepTimeout;
if (now < nextTimeout) {
//走到这个分支，应该是屏幕已经熄灭，但还未到达休眠状态，先进入dream态
mUserActivitySummary = USER_ACTIVITY_SCREEN_DREAM;
} else {
//直接进入dream态，后文的updateWakefulnessLocked将判断是否休眠
mUserActivitySummary = USER_ACTIVITY_SCREEN_DREAM;
nextTimeout = -1;
//如果屏幕未进入dream态，但Window Manager判定用户inactive，则进入下面分支
if (mUserActivitySummary != USER_ACTIVITY_SCREEN_DREAM && userInactiveOverride) {
//如果屏幕未熄灭
if ((mUserActivitySummary &
(USER_ACTIVITY_SCREEN_BRIGHT | USER_ACTIVITY_SCREEN_DIM)) != 0) {
// Device is being kept awake by recent user activity
if (nextTimeout >= now && mOverriddenTimeout == -1) {
// Save when the next timeout would have occurred
mOverriddenTimeout = nextTimeout;
//Window Manager的权限很大，如果它判断用户inactive，直接进入dream态
mUserActivitySummary = USER_ACTIVITY_SCREEN_DREAM;
nextTimeout = -1;
//根据nextTimeOut延迟发送信息，信息被处理后，将重新调用updatePowerStateLocked，于是再次进入到该方法
//通过不断进入该方法，不断评估是否根据用户动作亮、熄屏等
if (mUserActivitySummary != 0 && nextTimeout >= 0) {
Message msg = mHandler.obtainMessage(MSG_USER_ACTIVITY_TIMEOUT);
msg.setAsynchronous(true);
mHandler.sendMessageAtTime(msg, nextTimeout);
} else {
mUserActivitySummary = 0;
..........
4.isItBedTimeYetLocked()方法，该方法判断当前设备是否将要进入睡眠状态，
返回值为对isBeKeptAwakeLocke()方法返回值取反，由mStayOn(是否屏幕常亮)、wakelockSummary、
userActivitySummary、mProximityPositive等决定，只要满足其中之一为ture,则说明无法进入睡眠，
也就说，要满足进入睡眠，相关属性值都为false。
private boolean isItBedTimeYetLocked() {
return mBootCompleted && !isBeingKeptAwakeLocked();
private boolean isBeingKeptAwakeLocked() {return mStayOn//屏幕是否保持常亮
|| mProximityPositive//接近传感器接近屏幕时为true
//处于awake状态
|| (mWakeLockSummary & WAKE_LOCK_STAY_AWAKE) != 0
//屏幕处于亮屏或者dim状态
|| (mUserActivitySummary & (USER_ACTIVITY_SCREEN_BRIGHT
| USER_ACTIVITY_SCREEN_DIM)) != 0
|| mScreenBrightnessBoostInProgress;//处于亮度增强中}
5.updateWakeLockSummaryLocked函数根据PMS当前持有的所有WakeLock，得到当前终端整体的信息，保存到mWakeLockSummary变量中
* Updates the value of mWakeLockSummary to summarize the state of all active wake locks.
* Note that most wake-locks are ignored when the system is asleep.
private void updateWakeLockSummaryLocked(int dirty) {
//PMS持有的WakeLock发生变化，或者唤醒状态发生变化时，才重新进行更新mWakeLockSummary
//例如：调用PMS的acquireWakeLock时，就会将dirty的DIRTY_WAKE_LOCKS位置1
if ((dirty & (DIRTY_WAKE_LOCKS | DIRTY_WAKEFULNESS)) != 0) {
mWakeLockSummary = 0;
final int numWakeLocks = mWakeLocks.size();
for (int i = 0; i < numWakeLocks; i++) {
final WakeLock wakeLock = mWakeLocks.get(i);
//这里只关注WakeLock的level
//下面的代码其实就是实现每个level WakeLock对应的注释信息
switch (wakeLock.mFlags & PowerManager.WAKE_LOCK_LEVEL_MASK) {
case PowerManager.PARTIAL_WAKE_LOCK:
//在分析PMS acquireWakeLock的流程时，已经提到过
//在doze模式下，不在白名单内的非系统应用申请PARTIAL_WAKE_LOCK时，将被disabled
if (!wakeLock.mDisabled) {
// We only respect this if the wake lock is not disabled.
mWakeLockSummary |= WAKE_LOCK_CPU;
break;
case PowerManager.FULL_WAKE_LOCK:
mWakeLockSummary |= WAKE_LOCK_SCREEN_BRIGHT | WAKE_LOCK_BUTTON_BRIGHT;
break;
case PowerManager.SCREEN_BRIGHT_WAKE_LOCK:
mWakeLockSummary |= WAKE_LOCK_SCREEN_BRIGHT;
break;
case PowerManager.SCREEN_DIM_WAKE_LOCK:
mWakeLockSummary |= WAKE_LOCK_SCREEN_DIM;
break;
case PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK:
mWakeLockSummary |= WAKE_LOCK_PROXIMITY_SCREEN_OFF;
break;
case PowerManager.DOZE_WAKE_LOCK:
mWakeLockSummary |= WAKE_LOCK_DOZE;
break;
case PowerManager.DRAW_WAKE_LOCK:
mWakeLockSummary |= WAKE_LOCK_DRAW;
break;
// Cancel wake locks that make no sense based on the current state.
//从下面的代码可以看出，PMS中的mWakefulness变量记录了终端当前的状态
//下面就是移除在特定状态下，没有意义的WakeLock
if (mWakefulness != WAKEFULNESS_DOZING) {
//如果不是Dozing状态,移除相应的wakeLock标志位
mWakeLockSummary &= ~(WAKE_LOCK_DOZE | WAKE_LOCK_DRAW);
if (mWakefulness == WAKEFULNESS_ASLEEP
|| (mWakeLockSummary & WAKE_LOCK_DOZE) != 0) {
//如果当前为Asleep或者有Doze的wakeLock锁的时候，应该移除掉屏幕亮度相关的wakeLock锁
mWakeLockSummary &= ~(WAKE_LOCK_SCREEN_BRIGHT | WAKE_LOCK_SCREEN_DIM
| WAKE_LOCK_BUTTON_BRIGHT);
if (mWakefulness == WAKEFULNESS_ASLEEP) {
//休眠时，sensor不再需要监听终端是否靠近物体，以触发亮灭屏
mWakeLockSummary &= ~WAKE_LOCK_PROXIMITY_SCREEN_OFF;
// Infer implied wake locks where necessary based on the current state.
//根据当前的状态，及PMS持有的WakeLock，推断出隐含的持锁需求
//例如：当PMS持有亮屏锁WAKE_LOCK_SCREEN_BRIGHT时，若当前终端为唤醒态
//那么CPU显然也需要处于唤醒态
if ((mWakeLockSummary & (WAKE_LOCK_SCREEN_BRIGHT | WAKE_LOCK_SCREEN_DIM)) != 0) {
if (mWakefulness == WAKEFULNESS_AWAKE) {
mWakeLockSummary |= WAKE_LOCK_CPU | WAKE_LOCK_STAY_AWAKE;
} else if (mWakefulness == WAKEFULNESS_DREAMING) {
mWakeLockSummary |= WAKE_LOCK_CPU;
if ((mWakeLockSummary & WAKE_LOCK_DRAW) != 0) {
mWakeLockSummary |= WAKE_LOCK_CPU;
...................
二.RK3288 Android 7.1 HDMI 休眠
diff --git a/frameworks/base/services/core/java/com/android/server/power/PowerManagerService.java b/frameworks/base/services/core/java/com/android/server/power/PowerManagerService.java
index d38a942..93ff2a1 100755
--- a/frameworks/base/services/core/java/com/android/server/power/PowerManagerService.java
+++ b/frameworks/base/services/core/java/com/android/server/power/PowerManagerService.java
@@ -93,6 +93,8 @@ import static android.os.PowerManagerInternal.WAKEFULNESS_DREAMING;
//FOR CEC
import android.hardware.hdmi.*;
import android.os.ServiceManager;
+import java.io.File;
+import java.util.Scanner;
@@ -1628,6 +1630,25 @@ public final class PowerManagerService extends SystemService
+ private static boolean isHdmiSwitchSet() {
+ File switchFile = new File("/sys/devices/virtual/switch/hdmi/state");
+ if (!switchFile.exists()) {
+ switchFile = new File("/sys/class/switch/hdmi/state");
+ try {
+ Scanner switchFileScanner = new Scanner(switchFile);
+ int switchValue = switchFileScanner.nextInt();
+ switchFileScanner.close();
+ return switchValue > 0;
+ } catch (Exception e) {
+ return false;
* Updates the value of mWakeLockSummary to summarize the state of all active wake locks.
* Note that most wake-locks are ignored when the system is asleep.
@@ -1642,7 +1663,13 @@ public final class PowerManagerService extends SystemService
final int numWakeLocks = mWakeLocks.size();
for (int i = 0; i < numWakeLocks; i++) {
final WakeLock wakeLock = mWakeLocks.get(i);
- switch (wakeLock.mFlags & PowerManager.WAKE_LOCK_LEVEL_MASK) {
+ int xhmFlags;
+ if(isHdmiSwitchSet()) {
+ xhmFlags = 1;
+ }else {
+ xhmFlags = wakeLock.mFlags;
+ }
+ switch (xhmFlags & PowerManager.WAKE_LOCK_LEVEL_MASK) {
case PowerManager.PARTIAL_WAKE_LOCK:
if (!wakeLock.mDisabled) {
// We only respect this if the wake lock is not disabled.
