diff --git a/core/res/res/values/config.xml b/core/res/res/values/config.xml
index 68df6f1..b0869ea 100755
--- a/core/res/res/values/config.xml
+++ b/core/res/res/values/config.xml
@@ -861,10 +861,34 @@
     <!-- Allow automatic adjusting of the screen brightness while dozing in low power state. -->
     <bool name="config_allowAutoBrightnessWhileDozing">false</bool>
 
+    <!-- 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
+         when adapting to brighter or darker environments.  This parameter controls how quickly
+         brightness changes occur in response to an observed change in light level that exceeds the
+         hysteresis threshold. -->
+    <integer name="config_autoBrightnessBrighteningLightDebounce">4000</integer>
+    <integer name="config_autoBrightnessDarkeningLightDebounce">8000</integer>
+
+    <!-- Light sensor event rate in milliseconds for automatic brightness control. -->
+    <integer name="config_autoBrightnessLightSensorRate">250</integer>
+
     <!-- If we allow automatic adjustment of screen brightness while dozing, how many times we want
          to reduce it to preserve the battery. Value of 100% means no scaling. -->
     <fraction name="config_screenAutoBrightnessDozeScaleFactor">100%</fraction>
 
+    <!-- When the screen is turned on, the previous estimate of the ambient light level at the time
+         the screen was turned off is restored and is used to determine the initial screen
+         brightness.
+
+         If this flag is true, then the ambient light level estimate will be promptly recomputed
+         after the warm-up interface and the screen brightness will be adjusted immediately.
+
+         If this flag is false, then the ambient light level estimate will be adjusted more
+         gradually in the same manner that normally happens when the screen is on according to the
+         brightening or dimming debounce thresholds.  As a result, it may take somewhat longer to
+         adapt to the environment.  This mode may be better suited for watches. -->
+    <bool name="config_autoBrightnessResetAmbientLuxAfterWarmUp">true</bool>
+
     <!-- Screen brightness used to dim the screen when the user activity
          timeout expires.  May be less than the minimum allowed brightness setting
          that can be set by the user. -->
diff --git a/core/res/res/values/symbols.xml b/core/res/res/values/symbols.xml
index bd69fb0..b676dfa 100755
--- a/core/res/res/values/symbols.xml
+++ b/core/res/res/values/symbols.xml
@@ -1586,6 +1586,7 @@
   <java-symbol type="bool" name="config_useAttentionLight" />
   <java-symbol type="bool" name="config_animateScreenLights" />
   <java-symbol type="bool" name="config_automatic_brightness_available" />
+  <java-symbol type="bool" name="config_autoBrightnessResetAmbientLuxAfterWarmUp" />
   <java-symbol type="bool" name="config_dozeAfterScreenOff" />
   <java-symbol type="bool" name="config_enableActivityRecognitionHardwareOverlay" />
   <java-symbol type="bool" name="config_enableFusedLocationOverlay" />
@@ -1641,6 +1642,9 @@
   <java-symbol type="id" name="replace_message" />
   <java-symbol type="fraction" name="config_dimBehindFadeDuration" />
   <java-symbol type="fraction" name="config_screenAutoBrightnessDozeScaleFactor" />
+  <java-symbol type="integer" name="config_autoBrightnessBrighteningLightDebounce"/>
+  <java-symbol type="integer" name="config_autoBrightnessDarkeningLightDebounce"/>
+  <java-symbol type="integer" name="config_autoBrightnessLightSensorRate"/>
   <java-symbol type="integer" name="config_carDockKeepsScreenOn" />
   <java-symbol type="integer" name="config_criticalBatteryWarningLevel" />
   <java-symbol type="integer" name="config_datause_notification_type" />
diff --git a/services/core/java/com/android/server/display/AutomaticBrightnessController.java b/services/core/java/com/android/server/display/AutomaticBrightnessController.java
index d919bf6..93d37f1 100644
--- a/services/core/java/com/android/server/display/AutomaticBrightnessController.java
+++ b/services/core/java/com/android/server/display/AutomaticBrightnessController.java
@@ -52,20 +52,9 @@
     // auto-brightness adjustment setting.
     private static final float SCREEN_AUTO_BRIGHTNESS_ADJUSTMENT_MAX_GAMMA = 3.0f;
 
-    // Light sensor event rate in milliseconds.
-    private static final int LIGHT_SENSOR_RATE_MILLIS = 1000;
-
     // Period of time in which to consider light samples in milliseconds.
     private static final int AMBIENT_LIGHT_HORIZON = 10000;
 
-    // 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
-    // when adapting to brighter or darker environments.  This parameter controls how quickly
-    // brightness changes occur in response to an observed change in light level that exceeds the
-    // hysteresis threshold.
-    private static final long BRIGHTENING_LIGHT_DEBOUNCE = 4000;
-    private static final long DARKENING_LIGHT_DEBOUNCE = 8000;
-
     // Hysteresis constraints for brightening or darkening.
     // The recent lux must have changed by at least this fraction relative to the
     // current ambient lux before a change will be considered.
@@ -121,6 +110,22 @@
     private final int mScreenBrightnessRangeMaximum;
     private final float mDozeScaleFactor;
 
+    // Light sensor event rate in milliseconds.
+    private final int mLightSensorRate;
+
+    // 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
+    // when adapting to brighter or darker environments.  This parameter controls how quickly
+    // brightness changes occur in response to an observed change in light level that exceeds the
+    // hysteresis threshold.
+    private final long mBrighteningLightDebounceConfig;
+    private final long mDarkeningLightDebounceConfig;
+
+    // If true immediately after the screen is turned on the controller will try to adjust the
+    // brightness based on the current sensor reads. If false, the controller will collect more data
+    // and only then decide whether to change brightness.
+    private final boolean mResetAmbientLuxAfterWarmUpConfig;
+
     // Amount of time to delay auto-brightness after screen on while waiting for
     // the light sensor to warm-up in milliseconds.
     // May be 0 if no warm-up is required.
@@ -176,7 +181,9 @@
 
     public AutomaticBrightnessController(Callbacks callbacks, Looper looper,
             SensorManager sensorManager, Spline autoBrightnessSpline, int lightSensorWarmUpTime,
-            int brightnessMin, int brightnessMax, float dozeScaleFactor) {
+            int brightnessMin, int brightnessMax, float dozeScaleFactor,
+            int lightSensorRate, long brighteningLightDebounceConfig,
+            long darkeningLightDebounceConfig, boolean resetAmbientLuxAfterWarmUpConfig) {
         mCallbacks = callbacks;
         mTwilight = LocalServices.getService(TwilightManager.class);
         mSensorManager = sensorManager;
@@ -185,9 +192,13 @@
         mScreenBrightnessRangeMaximum = brightnessMax;
         mLightSensorWarmUpTimeConfig = lightSensorWarmUpTime;
         mDozeScaleFactor = dozeScaleFactor;
+        mLightSensorRate = lightSensorRate;
+        mBrighteningLightDebounceConfig = brighteningLightDebounceConfig;
+        mDarkeningLightDebounceConfig = darkeningLightDebounceConfig;
+        mResetAmbientLuxAfterWarmUpConfig = resetAmbientLuxAfterWarmUpConfig;
 
         mHandler = new AutomaticBrightnessHandler(looper);
-        mAmbientLightRingBuffer = new AmbientLightRingBuffer();
+        mAmbientLightRingBuffer = new AmbientLightRingBuffer(mLightSensorRate);
 
         if (!DEBUG_PRETEND_LIGHT_SENSOR_ABSENT) {
             mLightSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_LIGHT);
@@ -226,6 +237,9 @@
         pw.println("  mScreenBrightnessRangeMinimum=" + mScreenBrightnessRangeMinimum);
         pw.println("  mScreenBrightnessRangeMaximum=" + mScreenBrightnessRangeMaximum);
         pw.println("  mLightSensorWarmUpTimeConfig=" + mLightSensorWarmUpTimeConfig);
+        pw.println("  mBrighteningLightDebounceConfig=" + mBrighteningLightDebounceConfig);
+        pw.println("  mDarkeningLightDebounceConfig=" + mDarkeningLightDebounceConfig);
+        pw.println("  mResetAmbientLuxAfterWarmUpConfig=" + mResetAmbientLuxAfterWarmUpConfig);
 
         pw.println();
         pw.println("Automatic Brightness Controller State:");
@@ -252,13 +266,13 @@
                 mLightSensorEnabled = true;
                 mLightSensorEnableTime = SystemClock.uptimeMillis();
                 mSensorManager.registerListener(mLightSensorListener, mLightSensor,
-                        LIGHT_SENSOR_RATE_MILLIS * 1000, mHandler);
+                        mLightSensorRate * 1000, mHandler);
                 return true;
             }
         } else {
             if (mLightSensorEnabled) {
                 mLightSensorEnabled = false;
-                mAmbientLuxValid = false;
+                mAmbientLuxValid = !mResetAmbientLuxAfterWarmUpConfig;
                 mRecentLightSamples = 0;
                 mAmbientLightRingBuffer.clear();
                 mHandler.removeMessages(MSG_UPDATE_AMBIENT_LUX);
@@ -347,7 +361,7 @@
             }
             earliestValidTime = mAmbientLightRingBuffer.getTime(i);
         }
-        return earliestValidTime + BRIGHTENING_LIGHT_DEBOUNCE;
+        return earliestValidTime + mBrighteningLightDebounceConfig;
     }
 
     private long nextAmbientLightDarkeningTransition(long time) {
@@ -359,7 +373,7 @@
             }
             earliestValidTime = mAmbientLightRingBuffer.getTime(i);
         }
-        return earliestValidTime + DARKENING_LIGHT_DEBOUNCE;
+        return earliestValidTime + mDarkeningLightDebounceConfig;
     }
 
     private void updateAmbientLux() {
@@ -420,7 +434,7 @@
         // should be enough time to decide whether we should actually transition to the new
         // weighted ambient lux or not.
         nextTransitionTime =
-                nextTransitionTime > time ? nextTransitionTime : time + LIGHT_SENSOR_RATE_MILLIS;
+                nextTransitionTime > time ? nextTransitionTime : time + mLightSensorRate;
         if (DEBUG) {
             Slog.d(TAG, "updateAmbientLux: Scheduling ambient lux update for "
                     + nextTransitionTime + TimeUtils.formatUptime(nextTransitionTime));
@@ -559,8 +573,6 @@
         // Proportional extra capacity of the buffer beyond the expected number of light samples
         // in the horizon
         private static final float BUFFER_SLACK = 1.5f;
-        private static final int DEFAULT_CAPACITY =
-            (int) Math.ceil(AMBIENT_LIGHT_HORIZON * BUFFER_SLACK / LIGHT_SENSOR_RATE_MILLIS);
         private float[] mRingLux;
         private long[] mRingTime;
         private int mCapacity;
@@ -571,8 +583,8 @@
         private int mEnd;
         private int mCount;
 
-        public AmbientLightRingBuffer() {
-            this(DEFAULT_CAPACITY);
+        public AmbientLightRingBuffer(long lightSensorRate) {
+            this((int) Math.ceil(AMBIENT_LIGHT_HORIZON * BUFFER_SLACK / lightSensorRate));
         }
 
         public AmbientLightRingBuffer(int initialCapacity) {
diff --git a/services/core/java/com/android/server/display/DisplayPowerController.java b/services/core/java/com/android/server/display/DisplayPowerController.java
index 78610ff..cf1f4b0 100644
--- a/services/core/java/com/android/server/display/DisplayPowerController.java
+++ b/services/core/java/com/android/server/display/DisplayPowerController.java
@@ -302,6 +302,15 @@
         mAllowAutoBrightnessWhileDozingConfig = resources.getBoolean(
                 com.android.internal.R.bool.config_allowAutoBrightnessWhileDozing);
 
+        int lightSensorRate = resources.getInteger(
+                com.android.internal.R.integer.config_autoBrightnessLightSensorRate);
+        long brighteningLightDebounce = resources.getInteger(
+                com.android.internal.R.integer.config_autoBrightnessBrighteningLightDebounce);
+        long darkeningLightDebounce = resources.getInteger(
+                com.android.internal.R.integer.config_autoBrightnessDarkeningLightDebounce);
+        boolean autoBrightnessResetAmbientLuxAfterWarmUp = resources.getBoolean(
+                com.android.internal.R.bool.config_autoBrightnessResetAmbientLuxAfterWarmUp);
+
         if (mUseSoftwareAutoBrightnessConfig) {
             int[] lux = resources.getIntArray(
                     com.android.internal.R.array.config_autoBrightnessLevels);
@@ -336,7 +345,9 @@
                 mAutomaticBrightnessController = new AutomaticBrightnessController(this,
                         handler.getLooper(), sensorManager, screenAutoBrightnessSpline,
                         lightSensorWarmUpTimeConfig, screenBrightnessRangeMinimum,
-                        mScreenBrightnessRangeMaximum, dozeScaleFactor);
+                        mScreenBrightnessRangeMaximum, dozeScaleFactor, lightSensorRate,
+                        brighteningLightDebounce, darkeningLightDebounce,
+                        autoBrightnessResetAmbientLuxAfterWarmUp);
             }
         }