Add initial ambient light sensor rate

Bug: 32153559
Test: Existing tests pass.

Change-Id: Ic54bded46f88991290ed1e4d2574f865b6f598ec

core/res/res/values/config.xml

@@ -1059,6 +1059,12 @@
     <integer name="config_autoBrightnessBrighteningLightDebounce">4000</integer>
     <integer name="config_autoBrightnessDarkeningLightDebounce">8000</integer>
 
+    <!-- Initial light sensor event rate in milliseconds for automatic brightness control. This is
+         used for obtaining the first light sample when the device stops dozing.
+
+         Set this to -1 to disable this feature. -->
+    <integer name="config_autoBrightnessInitialLightSensorRate">-1</integer>
+
     <!-- Light sensor event rate in milliseconds for automatic brightness control. -->
     <integer name="config_autoBrightnessLightSensorRate">250</integer>
 

core/res/res/values/symbols.xml

@@ -1735,6 +1735,7 @@
   <java-symbol type="integer" name="config_autoBrightnessAmbientLightHorizon"/>
   <java-symbol type="integer" name="config_autoBrightnessBrighteningLightDebounce"/>
   <java-symbol type="integer" name="config_autoBrightnessDarkeningLightDebounce"/>
+  <java-symbol type="integer" name="config_autoBrightnessInitialLightSensorRate"/>
   <java-symbol type="integer" name="config_autoBrightnessLightSensorRate"/>
   <java-symbol type="integer" name="config_carDockKeepsScreenOn" />
   <java-symbol type="integer" name="config_criticalBatteryWarningLevel" />

services/core/java/com/android/server/display/AutomaticBrightnessController.java

@@ -86,8 +86,14 @@ class AutomaticBrightnessController {
     private final int mScreenBrightnessRangeMaximum;
     private final float mDozeScaleFactor;
 
-    // Light sensor event rate in milliseconds.
-    private final int mLightSensorRate;
+    // Initial light sensor event rate in milliseconds.
+    private final int mInitialLightSensorRate;
+
+    // Steady-state light sensor event rate in milliseconds.
+    private final int mNormalLightSensorRate;
+
+    // The current light sensor event rate in milliseconds.
+    private int mCurrentLightSensorRate;
 
     // Stability requirements in milliseconds for accepting a new brightness level.  This is used
     // for debouncing the light sensor.  Different constants are used to debounce the light sensor
@@ -185,7 +191,7 @@ class AutomaticBrightnessController {
     public AutomaticBrightnessController(Callbacks callbacks, Looper looper,
             SensorManager sensorManager, Spline autoBrightnessSpline, int lightSensorWarmUpTime,
             int brightnessMin, int brightnessMax, float dozeScaleFactor,
-            int lightSensorRate, long brighteningLightDebounceConfig,
+            int lightSensorRate, int initialLightSensorRate, long brighteningLightDebounceConfig,
             long darkeningLightDebounceConfig, boolean resetAmbientLuxAfterWarmUpConfig,
             int ambientLightHorizon, float autoBrightnessAdjustmentMaxGamma,
             HysteresisLevels dynamicHysteresis) {
@@ -197,7 +203,9 @@ class AutomaticBrightnessController {
         mScreenBrightnessRangeMaximum = brightnessMax;
         mLightSensorWarmUpTimeConfig = lightSensorWarmUpTime;
         mDozeScaleFactor = dozeScaleFactor;
-        mLightSensorRate = lightSensorRate;
+        mNormalLightSensorRate = lightSensorRate;
+        mInitialLightSensorRate = initialLightSensorRate;
+        mCurrentLightSensorRate = -1;
         mBrighteningLightDebounceConfig = brighteningLightDebounceConfig;
         mDarkeningLightDebounceConfig = darkeningLightDebounceConfig;
         mResetAmbientLuxAfterWarmUpConfig = resetAmbientLuxAfterWarmUpConfig;
@@ -208,9 +216,9 @@ class AutomaticBrightnessController {
 
         mHandler = new AutomaticBrightnessHandler(looper);
         mAmbientLightRingBuffer =
-            new AmbientLightRingBuffer(mLightSensorRate, mAmbientLightHorizon);
+            new AmbientLightRingBuffer(mNormalLightSensorRate, mAmbientLightHorizon);
         mInitialHorizonAmbientLightRingBuffer =
-            new AmbientLightRingBuffer(mLightSensorRate, mAmbientLightHorizon);
+            new AmbientLightRingBuffer(mNormalLightSensorRate, mAmbientLightHorizon);
 
         if (!DEBUG_PRETEND_LIGHT_SENSOR_ABSENT) {
             mLightSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_LIGHT);
@@ -293,8 +301,9 @@ class AutomaticBrightnessController {
             if (!mLightSensorEnabled) {
                 mLightSensorEnabled = true;
                 mLightSensorEnableTime = SystemClock.uptimeMillis();
+                mCurrentLightSensorRate = mInitialLightSensorRate;
                 mSensorManager.registerListener(mLightSensorListener, mLightSensor,
-                        mLightSensorRate * 1000, mHandler);
+                        mCurrentLightSensorRate * 1000, mHandler);
                 return true;
             }
         } else {
@@ -304,6 +313,7 @@ class AutomaticBrightnessController {
                 mRecentLightSamples = 0;
                 mAmbientLightRingBuffer.clear();
                 mInitialHorizonAmbientLightRingBuffer.clear();
+                mCurrentLightSensorRate = -1;
                 mHandler.removeMessages(MSG_UPDATE_AMBIENT_LUX);
                 mSensorManager.unregisterListener(mLightSensorListener);
             }
@@ -314,6 +324,10 @@ class AutomaticBrightnessController {
     private void handleLightSensorEvent(long time, float lux) {
         mHandler.removeMessages(MSG_UPDATE_AMBIENT_LUX);
 
+        if (mAmbientLightRingBuffer.size() == 0) {
+            // switch to using the steady-state sample rate after grabbing the initial light sample
+            adjustLightSensorRate(mNormalLightSensorRate);
+        }
         applyLightSensorMeasurement(time, lux);
         updateAmbientLux(time);
     }
@@ -333,6 +347,20 @@ class AutomaticBrightnessController {
         mLastObservedLuxTime = time;
     }
 
+    private void adjustLightSensorRate(int lightSensorRate) {
+        // if the light sensor rate changed, update the sensor listener
+        if (lightSensorRate != mCurrentLightSensorRate) {
+            if (DEBUG) {
+                Slog.d(TAG, "adjustLightSensorRate: previousRate=" + mCurrentLightSensorRate
+                    + ", currentRate=" + lightSensorRate);
+            }
+            mCurrentLightSensorRate = lightSensorRate;
+            mSensorManager.unregisterListener(mLightSensorListener);
+            mSensorManager.registerListener(mLightSensorListener, mLightSensor,
+                    lightSensorRate * 1000, mHandler);
+        }
+    }
+
     private boolean setScreenAutoBrightnessAdjustment(float adjustment) {
         if (adjustment != mScreenAutoBrightnessAdjustment) {
             mScreenAutoBrightnessAdjustment = adjustment;
@@ -468,7 +496,7 @@ class AutomaticBrightnessController {
         // should be enough time to decide whether we should actually transition to the new
         // weighted ambient lux or not.
         nextTransitionTime =
-                nextTransitionTime > time ? nextTransitionTime : time + mLightSensorRate;
+                nextTransitionTime > time ? nextTransitionTime : time + mNormalLightSensorRate;
         if (DEBUG) {
             Slog.d(TAG, "updateAmbientLux: Scheduling ambient lux update for "
                     + nextTransitionTime + TimeUtils.formatUptime(nextTransitionTime));

services/core/java/com/android/server/display/DisplayPowerController.java

@@ -310,6 +310,15 @@ final class DisplayPowerController implements AutomaticBrightnessController.Call
 
         int lightSensorRate = resources.getInteger(
                 com.android.internal.R.integer.config_autoBrightnessLightSensorRate);
+        int initialLightSensorRate = resources.getInteger(
+                com.android.internal.R.integer.config_autoBrightnessInitialLightSensorRate);
+        if (initialLightSensorRate == -1) {
+          initialLightSensorRate = lightSensorRate;
+        } else if (initialLightSensorRate > lightSensorRate) {
+          Slog.w(TAG, "Expected config_autoBrightnessInitialLightSensorRate ("
+                  + initialLightSensorRate + ") to be less than or equal to "
+                  + "config_autoBrightnessLightSensorRate (" + lightSensorRate + ").");
+        }
         long brighteningLightDebounce = resources.getInteger(
                 com.android.internal.R.integer.config_autoBrightnessBrighteningLightDebounce);
         long darkeningLightDebounce = resources.getInteger(
@@ -366,7 +375,7 @@ final class DisplayPowerController implements AutomaticBrightnessController.Call
                         handler.getLooper(), sensorManager, screenAutoBrightnessSpline,
                         lightSensorWarmUpTimeConfig, screenBrightnessRangeMinimum,
                         mScreenBrightnessRangeMaximum, dozeScaleFactor, lightSensorRate,
-                        brighteningLightDebounce, darkeningLightDebounce,
+                        initialLightSensorRate, brighteningLightDebounce, darkeningLightDebounce,
                         autoBrightnessResetAmbientLuxAfterWarmUp, ambientLightHorizon,
                         autoBrightnessAdjustmentMaxGamma, dynamicHysteresis);
             }