Set screen brightness to match sensor at power on.

Use the first sensor value received after screen on to set the screen
brightness. Do this setting immediately rather than animate to the
target brightness.

Fixes bug 6612418.

Change-Id: I6c24c55e0bd35ef58a6494d3b5e449954241fd00

Author: Craig Mautner

services/java/com/android/server/PowerManagerService.java

@@ -244,6 +244,7 @@ public class PowerManagerService extends IPowerManager.Stub
     private Handler mHandler;
     private final TimeoutTask mTimeoutTask = new TimeoutTask();
     private ScreenBrightnessAnimator mScreenBrightnessAnimator;
+    private boolean mWaitingForFirstLightSensor = false;
     private boolean mStillNeedSleepNotification;
     private boolean mIsPowered = false;
     private IActivityManager mActivityService;
@@ -1755,7 +1756,11 @@ private int setScreenStateLocked(boolean on) {
             mLastScreenOnTime = (on ? SystemClock.elapsedRealtime() : 0);
             if (mUseSoftwareAutoBrightness) {
                 enableLightSensorLocked(on);
-                if (!on) {
+                if (on) {
+                    // If AutoBrightness is enabled, set the brightness immediately after the
+                    // next sensor value is received.
+                    mWaitingForFirstLightSensor = mAutoBrightessEnabled;
+                } else {
                     // make sure button and key backlights are off too
                     mButtonLight.turnOff();
                     mKeyboardLight.turnOff();
@@ -2636,7 +2641,7 @@ private void dockStateChanged(int state) {
 
     private void lightSensorChangedLocked(int value, boolean immediate) {
         if (mDebugLightSensor) {
-            Slog.d(TAG, "lightSensorChangedLocked " + value);
+            Slog.d(TAG, "lightSensorChangedLocked value=" + value + " immediate=" + immediate);
         }
 
         // Don't do anything if the screen is off.
@@ -3212,7 +3217,9 @@ private void proximityChangedLocked(boolean active) {
     private void enableLightSensorLocked(boolean enable) {
         if (mDebugLightSensor) {
             Slog.d(TAG, "enableLightSensorLocked enable=" + enable
-                    + " mAutoBrightessEnabled=" + mAutoBrightessEnabled);
+                    + " mLightSensorEnabled=" + mLightSensorEnabled
+                    + " mAutoBrightessEnabled=" + mAutoBrightessEnabled
+                    + " mWaitingForFirstLightSensor=" + mWaitingForFirstLightSensor);
         }
         if (!mAutoBrightessEnabled) {
             enable = false;
@@ -3226,8 +3233,8 @@ private void enableLightSensorLocked(boolean enable) {
                     // reset our highest value when reenabling
                     mHighestLightSensorValue = -1;
                     // force recompute of backlight values
-                    if (mLightSensorValue >= 0) {
-                        int value = (int)mLightSensorValue;
+                    final int value = (int)mLightSensorValue;
+                    if (value >= 0) {
                         mLightSensorValue = -1;
                         handleLightSensorValue(value, true);
                     }
@@ -3291,8 +3298,9 @@ public void onAccuracyChanged(Sensor sensor, int accuracy) {
 
     private void handleLightSensorValue(int value, boolean immediate) {
         long milliseconds = SystemClock.elapsedRealtime();
-        if (mLightSensorValue == -1 ||
-                milliseconds < mLastScreenOnTime + mLightSensorWarmupTime) {
+        if (mLightSensorValue == -1
+                || milliseconds < mLastScreenOnTime + mLightSensorWarmupTime
+                || mWaitingForFirstLightSensor) {
             // process the value immediately if screen has just turned on
             mHandler.removeCallbacks(mAutoBrightnessTask);
             mLightSensorPendingDecrease = false;
@@ -3327,7 +3335,10 @@ public void onSensorChanged(SensorEvent event) {
                 if (isScreenTurningOffLocked()) {
                     return;
                 }
-                handleLightSensorValue((int)event.values[0], false);
+                handleLightSensorValue((int)event.values[0], mWaitingForFirstLightSensor);
+                if (mWaitingForFirstLightSensor) {
+                    mWaitingForFirstLightSensor = false;
+                }
             }
         }