diff --git a/services/java/com/android/server/PowerManagerService.java b/services/java/com/android/server/PowerManagerService.java
index e1b909952cf..ee022fb1e6a 100644
--- a/services/java/com/android/server/PowerManagerService.java
+++ b/services/java/com/android/server/PowerManagerService.java
@@ -258,6 +258,12 @@ public class PowerManagerService extends IPowerManager.Stub
     private int mAnimationSetting = ANIM_SETTING_OFF;
     private boolean mAnimateCrtOff = false;
     private boolean mAnimateCrtOn = false;
+        // When using software auto-brightness, determines whether (true) button
+	// and keyboard backlights should also be under automatic brightness
+	// control (i.e., for dimmable backlights), or (false) if they should use
+	// hard-coded brightness settings that timeout-to-off in subsequent screen
+	// power states.
+	private boolean mAutobrightnessButtonKeyboard;
 
     // Must match with the ISurfaceComposer constants in C++.
     private static final int ANIM_SETTING_ON = 0x01;
@@ -617,6 +623,8 @@ void initInThread() {
         // read settings for auto-brightness
         mUseSoftwareAutoBrightness = resources.getBoolean(
                 com.android.internal.R.bool.config_automatic_brightness_available);
+		mAutoBrightnessButtonKeyboard = mUseSoftwareAutoBrightness && resources.getBoolean(
+				com.android.internal.R.bool.config_autoBrightnessButtonKeyboard);
         if (mUseSoftwareAutoBrightness) {
             mAutoBrightnessLevels = resources.getIntArray(
                     com.android.internal.R.array.config_autoBrightnessLevels);
@@ -822,7 +830,7 @@ public void acquireWakeLockLocked(int flags, IBinder lock, int uid, int pid, Str
             switch (wl.flags & LOCK_MASK)
             {
                 case PowerManager.FULL_WAKE_LOCK:
-                    if (mUseSoftwareAutoBrightness) {
+                    if (mAutoBrightnessButtonKeyboard) {
                         wl.minState = SCREEN_BRIGHT;
                     } else {
                         wl.minState = (mKeyboardVisible ? ALL_BRIGHT : SCREEN_BUTTON_BRIGHT);
@@ -1189,6 +1197,7 @@ public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
                     + " mLightSensorButtonBrightness=" + mLightSensorButtonBrightness
                     + " mLightSensorKeyboardBrightness=" + mLightSensorKeyboardBrightness);
             pw.println("  mUseSoftwareAutoBrightness=" + mUseSoftwareAutoBrightness);
+			pw.println("  mAutoBrightnessButtonKeyboard=" + mAutoBrightnessButtonKeyboard);
             pw.println("  mAutoBrightessEnabled=" + mAutoBrightessEnabled);
             mScreenBrightness.dump(pw, "  mScreenBrightness: ");
 
@@ -1768,7 +1777,7 @@ private void setPowerState(int newState, boolean noChangeLights, int reason)
                 return;
             }
 
-            if (!mBootCompleted && !mUseSoftwareAutoBrightness) {
+            if (!mBootCompleted && !mAutoBrightnessButtonKeyboard) {
                 newState |= ALL_BRIGHT;
             }
 
@@ -2280,7 +2289,7 @@ private int applyButtonState(int state) {
         }
         if (mButtonBrightnessOverride >= 0) {
             brightness = mButtonBrightnessOverride;
-        } else if (mLightSensorButtonBrightness >= 0 && mUseSoftwareAutoBrightness) {
+        } else if (mLightSensorButtonBrightness >= 0 && mAutoBrightnessButtonKeyboard) {
             brightness = mLightSensorButtonBrightness;
         }
         if (brightness > 0) {
@@ -2302,7 +2311,7 @@ private int applyKeyboardState(int state) {
             brightness = 0;
         } else if (mButtonBrightnessOverride >= 0) {
             brightness = mButtonBrightnessOverride;
-        } else if (mLightSensorKeyboardBrightness >= 0 && mUseSoftwareAutoBrightness) {
+        } else if (mLightSensorKeyboardBrightness >= 0 && mAutoBrightnessButtonKeyboard) {
             brightness =  mLightSensorKeyboardBrightness;
         }
         if (brightness > 0) {
@@ -2425,9 +2434,11 @@ private void userActivity(long time, long timeoutOverride, boolean noChangeLight
             if (mLastEventTime <= time || force) {
                 mLastEventTime = time;
                 if ((mUserActivityAllowed && !mProximitySensorActive) || force) {
-                    // Only turn on button backlights if a button was pressed
-                    // and auto brightness is disabled
-                    if (eventType == BUTTON_EVENT && !mUseSoftwareAutoBrightness) {
+					if (!mAutoBrightnessButtonKeyboard) {
+						// Turn on button (and keyboard) backlights on any event, so that they
+						// don't suddenly disappear when the lock screen is unlocked (OTHER_EVENT),
+						// and so capacitive buttons can be found on devices where they lack
+						// identifying surface features.
                         mUserState = (mKeyboardVisible ? ALL_BRIGHT : SCREEN_BUTTON_BRIGHT);
                     } else {
                         // don't clear button/keyboard backlights when the screen is touched.
@@ -2899,7 +2910,7 @@ void systemReady() {
         // wait until sensors are enabled before turning on screen.
         // some devices will not activate the light sensor properly on boot
         // unless we do this.
-        if (mUseSoftwareAutoBrightness) {
+        if (mAutoBrightnessButtonKeyboard) {
             // turn the screen on
             setPowerState(SCREEN_BRIGHT);
         } else {