com/android/server/display/DisplayPowerState.java - platform/prebuilts/fullsdk/sources/android-28 - Git at Google

 /*
  * Copyright (C) 2012 The Android Open Source Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package com.android.server.display;

 import android.content.Context;
 import android.os.Handler;
 import android.os.Looper;
 import android.os.PowerManager;
 import android.os.Trace;
 import android.util.FloatProperty;
 import android.util.IntProperty;
 import android.util.Slog;
 import android.view.Choreographer;
 import android.view.Display;

 import java.io.PrintWriter;

 /**
  * Controls the display power state.
  * <p>
  * This component is similar in nature to a {@link android.view.View} except that it
  * describes the properties of a display.  When properties are changed, the component
  * invalidates itself and posts a callback to apply the changes in a consistent order.
  * This mechanism enables multiple properties of the display power state to be animated
  * together smoothly by the animation framework.  Some of the work to blank or unblank
  * the display is done on a separate thread to avoid blocking the looper.
  * </p><p>
  * This component must only be created or accessed by the {@link Looper} thread
  * that belongs to the {@link DisplayPowerController}.
  * </p><p>
  * We don't need to worry about holding a suspend blocker here because the
  * power manager does that for us whenever there is a change in progress.
  * </p>
  */
 final class DisplayPowerState {
     private static final String TAG = "DisplayPowerState";

     private static boolean DEBUG = false;
     private static String COUNTER_COLOR_FADE = "ColorFadeLevel";

     private final Handler mHandler;
     private final Choreographer mChoreographer;
     private final DisplayBlanker mBlanker;
     private final ColorFade mColorFade;
     private final PhotonicModulator mPhotonicModulator;

     private int mScreenState;
     private int mScreenBrightness;
     private boolean mScreenReady;
     private boolean mScreenUpdatePending;

     private boolean mColorFadePrepared;
     private float mColorFadeLevel;
     private boolean mColorFadeReady;
     private boolean mColorFadeDrawPending;

     private Runnable mCleanListener;

     public DisplayPowerState(DisplayBlanker blanker, ColorFade colorFade) {
         mHandler = new Handler(true /*async*/);
         mChoreographer = Choreographer.getInstance();
         mBlanker = blanker;
         mColorFade = colorFade;
         mPhotonicModulator = new PhotonicModulator();
         mPhotonicModulator.start();

         // At boot time, we know that the screen is on and the electron beam
         // animation is not playing.  We don't know the screen's brightness though,
         // so prepare to set it to a known state when the state is next applied.
         // Although we set the brightness to full on here, the display power controller
         // will reset the brightness to a new level immediately before the changes
         // actually have a chance to be applied.
         mScreenState = Display.STATE_ON;
         mScreenBrightness = PowerManager.BRIGHTNESS_ON;
         scheduleScreenUpdate();

         mColorFadePrepared = false;
         mColorFadeLevel = 1.0f;
         mColorFadeReady = true;
     }

     public static final FloatProperty<DisplayPowerState> COLOR_FADE_LEVEL =
             new FloatProperty<DisplayPowerState>("electronBeamLevel") {
         @Override
         public void setValue(DisplayPowerState object, float value) {
             object.setColorFadeLevel(value);
         }

         @Override
         public Float get(DisplayPowerState object) {
             return object.getColorFadeLevel();
         }
     };

     public static final IntProperty<DisplayPowerState> SCREEN_BRIGHTNESS =
             new IntProperty<DisplayPowerState>("screenBrightness") {
         @Override
         public void setValue(DisplayPowerState object, int value) {
             object.setScreenBrightness(value);
         }

         @Override
         public Integer get(DisplayPowerState object) {
             return object.getScreenBrightness();
         }
     };

     /**
      * Sets whether the screen is on, off, or dozing.
      */
     public void setScreenState(int state) {
         if (mScreenState != state) {
             if (DEBUG) {
                 Slog.d(TAG, "setScreenState: state=" + state);
             }

             mScreenState = state;
             mScreenReady = false;
             scheduleScreenUpdate();
         }
     }

     /**
      * Gets the desired screen state.
      */
     public int getScreenState() {
         return mScreenState;
     }

     /**
      * Sets the display brightness.
      *
      * @param brightness The brightness, ranges from 0 (minimum / off) to 255 (brightest).
      */
     public void setScreenBrightness(int brightness) {
         if (mScreenBrightness != brightness) {
             if (DEBUG) {
                 Slog.d(TAG, "setScreenBrightness: brightness=" + brightness);
             }

             mScreenBrightness = brightness;
             if (mScreenState != Display.STATE_OFF) {
                 mScreenReady = false;
                 scheduleScreenUpdate();
             }
         }
     }

     /**
      * Gets the screen brightness.
      */
     public int getScreenBrightness() {
         return mScreenBrightness;
     }

     /**
      * Prepares the electron beam to turn on or off.
      * This method should be called before starting an animation because it
      * can take a fair amount of time to prepare the electron beam surface.
      *
      * @param mode The electron beam animation mode to prepare.
      * @return True if the electron beam was prepared.
      */
     public boolean prepareColorFade(Context context, int mode) {
         if (mColorFade == null || !mColorFade.prepare(context, mode)) {
             mColorFadePrepared = false;
             mColorFadeReady = true;
             return false;
         }

         mColorFadePrepared = true;
         mColorFadeReady = false;
         scheduleColorFadeDraw();
         return true;
     }

     /**
      * Dismisses the color fade surface.
      */
     public void dismissColorFade() {
         Trace.traceCounter(Trace.TRACE_TAG_POWER, COUNTER_COLOR_FADE, 100);
         if (mColorFade != null) mColorFade.dismiss();
         mColorFadePrepared = false;
         mColorFadeReady = true;
     }

    /**
      * Dismisses the color fade resources.
      */
     public void dismissColorFadeResources() {
         if (mColorFade != null) mColorFade.dismissResources();
     }

     /**
      * Sets the level of the electron beam steering current.
      *
      * The display is blanked when the level is 0.0.  In normal use, the electron
      * beam should have a value of 1.0.  The electron beam is unstable in between
      * these states and the picture quality may be compromised.  For best effect,
      * the electron beam should be warmed up or cooled off slowly.
      *
      * Warning: Electron beam emits harmful radiation.  Avoid direct exposure to
      * skin or eyes.
      *
      * @param level The level, ranges from 0.0 (full off) to 1.0 (full on).
      */
     public void setColorFadeLevel(float level) {
         if (mColorFadeLevel != level) {
             if (DEBUG) {
                 Slog.d(TAG, "setColorFadeLevel: level=" + level);
             }

             mColorFadeLevel = level;
             if (mScreenState != Display.STATE_OFF) {
                 mScreenReady = false;
                 scheduleScreenUpdate(); // update backlight brightness
             }
             if (mColorFadePrepared) {
                 mColorFadeReady = false;
                 scheduleColorFadeDraw();
             }
         }
     }

     /**
      * Gets the level of the electron beam steering current.
      */
     public float getColorFadeLevel() {
         return mColorFadeLevel;
     }

     /**
      * Returns true if no properties have been invalidated.
      * Otherwise, returns false and promises to invoke the specified listener
      * when the properties have all been applied.
      * The listener always overrides any previously set listener.
      */
     public boolean waitUntilClean(Runnable listener) {
         if (!mScreenReady || !mColorFadeReady) {
             mCleanListener = listener;
             return false;
         } else {
             mCleanListener = null;
             return true;
         }
     }

     public void dump(PrintWriter pw) {
         pw.println();
         pw.println("Display Power State:");
         pw.println("  mScreenState=" + Display.stateToString(mScreenState));
         pw.println("  mScreenBrightness=" + mScreenBrightness);
         pw.println("  mScreenReady=" + mScreenReady);
         pw.println("  mScreenUpdatePending=" + mScreenUpdatePending);
         pw.println("  mColorFadePrepared=" + mColorFadePrepared);
         pw.println("  mColorFadeLevel=" + mColorFadeLevel);
         pw.println("  mColorFadeReady=" + mColorFadeReady);
         pw.println("  mColorFadeDrawPending=" + mColorFadeDrawPending);

         mPhotonicModulator.dump(pw);
         if (mColorFade != null) mColorFade.dump(pw);
     }

     private void scheduleScreenUpdate() {
         if (!mScreenUpdatePending) {
             mScreenUpdatePending = true;
             postScreenUpdateThreadSafe();
         }
     }

     private void postScreenUpdateThreadSafe() {
         mHandler.removeCallbacks(mScreenUpdateRunnable);
         mHandler.post(mScreenUpdateRunnable);
     }

     private void scheduleColorFadeDraw() {
         if (!mColorFadeDrawPending) {
             mColorFadeDrawPending = true;
             mChoreographer.postCallback(Choreographer.CALLBACK_TRAVERSAL,
                     mColorFadeDrawRunnable, null);
         }
     }

     private void invokeCleanListenerIfNeeded() {
         final Runnable listener = mCleanListener;
         if (listener != null && mScreenReady && mColorFadeReady) {
             mCleanListener = null;
             listener.run();
         }
     }

     private final Runnable mScreenUpdateRunnable = new Runnable() {
         @Override
         public void run() {
             mScreenUpdatePending = false;

             int brightness = mScreenState != Display.STATE_OFF
                     && mColorFadeLevel > 0f ? mScreenBrightness : 0;
             if (mPhotonicModulator.setState(mScreenState, brightness)) {
                 if (DEBUG) {
                     Slog.d(TAG, "Screen ready");
                 }
                 mScreenReady = true;
                 invokeCleanListenerIfNeeded();
             } else {
                 if (DEBUG) {
                     Slog.d(TAG, "Screen not ready");
                 }
             }
         }
     };

     private final Runnable mColorFadeDrawRunnable = new Runnable() {
         @Override
         public void run() {
             mColorFadeDrawPending = false;

             if (mColorFadePrepared) {
                 mColorFade.draw(mColorFadeLevel);
                 Trace.traceCounter(Trace.TRACE_TAG_POWER,
                         COUNTER_COLOR_FADE, Math.round(mColorFadeLevel * 100));
             }

             mColorFadeReady = true;
             invokeCleanListenerIfNeeded();
         }
     };

     /**
      * Updates the state of the screen and backlight asynchronously on a separate thread.
      */
     private final class PhotonicModulator extends Thread {
         private static final int INITIAL_SCREEN_STATE = Display.STATE_OFF; // unknown, assume off
         private static final int INITIAL_BACKLIGHT = -1; // unknown

         private final Object mLock = new Object();

         private int mPendingState = INITIAL_SCREEN_STATE;
         private int mPendingBacklight = INITIAL_BACKLIGHT;
         private int mActualState = INITIAL_SCREEN_STATE;
         private int mActualBacklight = INITIAL_BACKLIGHT;
         private boolean mStateChangeInProgress;
         private boolean mBacklightChangeInProgress;

         public PhotonicModulator() {
             super("PhotonicModulator");
         }

         public boolean setState(int state, int backlight) {
             synchronized (mLock) {
                 boolean stateChanged = state != mPendingState;
                 boolean backlightChanged = backlight != mPendingBacklight;
                 if (stateChanged || backlightChanged) {
                     if (DEBUG) {
                         Slog.d(TAG, "Requesting new screen state: state="
                                 + Display.stateToString(state) + ", backlight=" + backlight);
                     }

                     mPendingState = state;
                     mPendingBacklight = backlight;

                     boolean changeInProgress = mStateChangeInProgress || mBacklightChangeInProgress;
                     mStateChangeInProgress = stateChanged || mStateChangeInProgress;
                     mBacklightChangeInProgress = backlightChanged || mBacklightChangeInProgress;

                     if (!changeInProgress) {
                         mLock.notifyAll();
                     }
                 }
                 return !mStateChangeInProgress;
             }
         }

         public void dump(PrintWriter pw) {
             synchronized (mLock) {
                 pw.println();
                 pw.println("Photonic Modulator State:");
                 pw.println("  mPendingState=" + Display.stateToString(mPendingState));
                 pw.println("  mPendingBacklight=" + mPendingBacklight);
                 pw.println("  mActualState=" + Display.stateToString(mActualState));
                 pw.println("  mActualBacklight=" + mActualBacklight);
                 pw.println("  mStateChangeInProgress=" + mStateChangeInProgress);
                 pw.println("  mBacklightChangeInProgress=" + mBacklightChangeInProgress);
             }
         }

         @Override
         public void run() {
             for (;;) {
                 // Get pending change.
                 final int state;
                 final boolean stateChanged;
                 final int backlight;
                 final boolean backlightChanged;
                 synchronized (mLock) {
                     state = mPendingState;
                     stateChanged = (state != mActualState);
                     backlight = mPendingBacklight;
                     backlightChanged = (backlight != mActualBacklight);
                     if (!stateChanged) {
                         // State changed applied, notify outer class.
                         postScreenUpdateThreadSafe();
                         mStateChangeInProgress = false;
                     }
                     if (!backlightChanged) {
                         mBacklightChangeInProgress = false;
                     }
                     if (!stateChanged && !backlightChanged) {
                         try {
                             mLock.wait();
                         } catch (InterruptedException ex) { }
                         continue;
                     }
                     mActualState = state;
                     mActualBacklight = backlight;
                 }

                 // Apply pending change.
                 if (DEBUG) {
                     Slog.d(TAG, "Updating screen state: state="
                             + Display.stateToString(state) + ", backlight=" + backlight);
                 }
                 mBlanker.requestDisplayState(state, backlight);
             }
         }
     }
 }
	/*
	* Copyright (C) 2012 The Android Open Source Project
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package com.android.server.display;

	import android.content.Context;
	import android.os.Handler;
	import android.os.Looper;
	import android.os.PowerManager;
	import android.os.Trace;
	import android.util.FloatProperty;
	import android.util.IntProperty;
	import android.util.Slog;
	import android.view.Choreographer;
	import android.view.Display;

	import java.io.PrintWriter;

	/**
	* Controls the display power state.
	* <p>
	* This component is similar in nature to a {@link android.view.View} except that it
	* describes the properties of a display. When properties are changed, the component
	* invalidates itself and posts a callback to apply the changes in a consistent order.
	* This mechanism enables multiple properties of the display power state to be animated
	* together smoothly by the animation framework. Some of the work to blank or unblank
	* the display is done on a separate thread to avoid blocking the looper.
	* </p><p>
	* This component must only be created or accessed by the {@link Looper} thread
	* that belongs to the {@link DisplayPowerController}.
	* </p><p>
	* We don't need to worry about holding a suspend blocker here because the
	* power manager does that for us whenever there is a change in progress.
	* </p>
	*/
	final class DisplayPowerState {
	private static final String TAG = "DisplayPowerState";

	private static boolean DEBUG = false;
	private static String COUNTER_COLOR_FADE = "ColorFadeLevel";

	private final Handler mHandler;
	private final Choreographer mChoreographer;
	private final DisplayBlanker mBlanker;
	private final ColorFade mColorFade;
	private final PhotonicModulator mPhotonicModulator;

	private int mScreenState;
	private int mScreenBrightness;
	private boolean mScreenReady;
	private boolean mScreenUpdatePending;

	private boolean mColorFadePrepared;
	private float mColorFadeLevel;
	private boolean mColorFadeReady;
	private boolean mColorFadeDrawPending;

	private Runnable mCleanListener;

	public DisplayPowerState(DisplayBlanker blanker, ColorFade colorFade) {
	mHandler = new Handler(true /async/);
	mChoreographer = Choreographer.getInstance();
	mBlanker = blanker;
	mColorFade = colorFade;
	mPhotonicModulator = new PhotonicModulator();
	mPhotonicModulator.start();

	// At boot time, we know that the screen is on and the electron beam
	// animation is not playing. We don't know the screen's brightness though,
	// so prepare to set it to a known state when the state is next applied.
	// Although we set the brightness to full on here, the display power controller
	// will reset the brightness to a new level immediately before the changes
	// actually have a chance to be applied.
	mScreenState = Display.STATE_ON;
	mScreenBrightness = PowerManager.BRIGHTNESS_ON;
	scheduleScreenUpdate();

	mColorFadePrepared = false;
	mColorFadeLevel = 1.0f;
	mColorFadeReady = true;
	}

	public static final FloatProperty<DisplayPowerState> COLOR_FADE_LEVEL =
	new FloatProperty<DisplayPowerState>("electronBeamLevel") {
	@Override
	public void setValue(DisplayPowerState object, float value) {
	object.setColorFadeLevel(value);
	}

	@Override
	public Float get(DisplayPowerState object) {
	return object.getColorFadeLevel();
	}
	};

	public static final IntProperty<DisplayPowerState> SCREEN_BRIGHTNESS =
	new IntProperty<DisplayPowerState>("screenBrightness") {
	@Override
	public void setValue(DisplayPowerState object, int value) {
	object.setScreenBrightness(value);
	}

	@Override
	public Integer get(DisplayPowerState object) {
	return object.getScreenBrightness();
	}
	};

	/**
	* Sets whether the screen is on, off, or dozing.
	*/
	public void setScreenState(int state) {
	if (mScreenState != state) {
	if (DEBUG) {
	Slog.d(TAG, "setScreenState: state=" + state);
	}

	mScreenState = state;
	mScreenReady = false;
	scheduleScreenUpdate();
	}
	}

	/**
	* Gets the desired screen state.
	*/
	public int getScreenState() {
	return mScreenState;
	}

	/**
	* Sets the display brightness.
	*
	* @param brightness The brightness, ranges from 0 (minimum / off) to 255 (brightest).
	*/
	public void setScreenBrightness(int brightness) {
	if (mScreenBrightness != brightness) {
	if (DEBUG) {
	Slog.d(TAG, "setScreenBrightness: brightness=" + brightness);
	}

	mScreenBrightness = brightness;
	if (mScreenState != Display.STATE_OFF) {
	mScreenReady = false;
	scheduleScreenUpdate();
	}
	}
	}

	/**
	* Gets the screen brightness.
	*/
	public int getScreenBrightness() {
	return mScreenBrightness;
	}

	/**
	* Prepares the electron beam to turn on or off.
	* This method should be called before starting an animation because it
	* can take a fair amount of time to prepare the electron beam surface.
	*
	* @param mode The electron beam animation mode to prepare.
	* @return True if the electron beam was prepared.
	*/
	public boolean prepareColorFade(Context context, int mode) {
	if (mColorFade == null \|\| !mColorFade.prepare(context, mode)) {
	mColorFadePrepared = false;
	mColorFadeReady = true;
	return false;
	}

	mColorFadePrepared = true;
	mColorFadeReady = false;
	scheduleColorFadeDraw();
	return true;
	}

	/**
	* Dismisses the color fade surface.
	*/
	public void dismissColorFade() {
	Trace.traceCounter(Trace.TRACE_TAG_POWER, COUNTER_COLOR_FADE, 100);
	if (mColorFade != null) mColorFade.dismiss();
	mColorFadePrepared = false;
	mColorFadeReady = true;
	}

	/**
	* Dismisses the color fade resources.
	*/
	public void dismissColorFadeResources() {
	if (mColorFade != null) mColorFade.dismissResources();
	}

	/**
	* Sets the level of the electron beam steering current.
	*
	* The display is blanked when the level is 0.0. In normal use, the electron
	* beam should have a value of 1.0. The electron beam is unstable in between
	* these states and the picture quality may be compromised. For best effect,
	* the electron beam should be warmed up or cooled off slowly.
	*
	* Warning: Electron beam emits harmful radiation. Avoid direct exposure to
	* skin or eyes.
	*
	* @param level The level, ranges from 0.0 (full off) to 1.0 (full on).
	*/
	public void setColorFadeLevel(float level) {
	if (mColorFadeLevel != level) {
	if (DEBUG) {
	Slog.d(TAG, "setColorFadeLevel: level=" + level);
	}

	mColorFadeLevel = level;
	if (mScreenState != Display.STATE_OFF) {
	mScreenReady = false;
	scheduleScreenUpdate(); // update backlight brightness
	}
	if (mColorFadePrepared) {
	mColorFadeReady = false;
	scheduleColorFadeDraw();
	}
	}
	}

	/**
	* Gets the level of the electron beam steering current.
	*/
	public float getColorFadeLevel() {
	return mColorFadeLevel;
	}

	/**
	* Returns true if no properties have been invalidated.
	* Otherwise, returns false and promises to invoke the specified listener
	* when the properties have all been applied.
	* The listener always overrides any previously set listener.
	*/
	public boolean waitUntilClean(Runnable listener) {
	if (!mScreenReady \|\| !mColorFadeReady) {
	mCleanListener = listener;
	return false;
	} else {
	mCleanListener = null;
	return true;
	}
	}

	public void dump(PrintWriter pw) {
	pw.println();
	pw.println("Display Power State:");
	pw.println(" mScreenState=" + Display.stateToString(mScreenState));
	pw.println(" mScreenBrightness=" + mScreenBrightness);
	pw.println(" mScreenReady=" + mScreenReady);
	pw.println(" mScreenUpdatePending=" + mScreenUpdatePending);
	pw.println(" mColorFadePrepared=" + mColorFadePrepared);
	pw.println(" mColorFadeLevel=" + mColorFadeLevel);
	pw.println(" mColorFadeReady=" + mColorFadeReady);
	pw.println(" mColorFadeDrawPending=" + mColorFadeDrawPending);

	mPhotonicModulator.dump(pw);
	if (mColorFade != null) mColorFade.dump(pw);
	}

	private void scheduleScreenUpdate() {
	if (!mScreenUpdatePending) {
	mScreenUpdatePending = true;
	postScreenUpdateThreadSafe();
	}
	}

	private void postScreenUpdateThreadSafe() {
	mHandler.removeCallbacks(mScreenUpdateRunnable);
	mHandler.post(mScreenUpdateRunnable);
	}

	private void scheduleColorFadeDraw() {
	if (!mColorFadeDrawPending) {
	mColorFadeDrawPending = true;
	mChoreographer.postCallback(Choreographer.CALLBACK_TRAVERSAL,
	mColorFadeDrawRunnable, null);
	}
	}

	private void invokeCleanListenerIfNeeded() {
	final Runnable listener = mCleanListener;
	if (listener != null && mScreenReady && mColorFadeReady) {
	mCleanListener = null;
	listener.run();
	}
	}

	private final Runnable mScreenUpdateRunnable = new Runnable() {
	@Override
	public void run() {
	mScreenUpdatePending = false;

	int brightness = mScreenState != Display.STATE_OFF
	&& mColorFadeLevel > 0f ? mScreenBrightness : 0;
	if (mPhotonicModulator.setState(mScreenState, brightness)) {
	if (DEBUG) {
	Slog.d(TAG, "Screen ready");
	}
	mScreenReady = true;
	invokeCleanListenerIfNeeded();
	} else {
	if (DEBUG) {
	Slog.d(TAG, "Screen not ready");
	}
	}
	}
	};

	private final Runnable mColorFadeDrawRunnable = new Runnable() {
	@Override
	public void run() {
	mColorFadeDrawPending = false;

	if (mColorFadePrepared) {
	mColorFade.draw(mColorFadeLevel);
	Trace.traceCounter(Trace.TRACE_TAG_POWER,
	COUNTER_COLOR_FADE, Math.round(mColorFadeLevel * 100));
	}

	mColorFadeReady = true;
	invokeCleanListenerIfNeeded();
	}
	};

	/**
	* Updates the state of the screen and backlight asynchronously on a separate thread.
	*/
	private final class PhotonicModulator extends Thread {
	private static final int INITIAL_SCREEN_STATE = Display.STATE_OFF; // unknown, assume off
	private static final int INITIAL_BACKLIGHT = -1; // unknown

	private final Object mLock = new Object();

	private int mPendingState = INITIAL_SCREEN_STATE;
	private int mPendingBacklight = INITIAL_BACKLIGHT;
	private int mActualState = INITIAL_SCREEN_STATE;
	private int mActualBacklight = INITIAL_BACKLIGHT;
	private boolean mStateChangeInProgress;
	private boolean mBacklightChangeInProgress;

	public PhotonicModulator() {
	super("PhotonicModulator");
	}

	public boolean setState(int state, int backlight) {
	synchronized (mLock) {
	boolean stateChanged = state != mPendingState;
	boolean backlightChanged = backlight != mPendingBacklight;
	if (stateChanged \|\| backlightChanged) {
	if (DEBUG) {
	Slog.d(TAG, "Requesting new screen state: state="
	+ Display.stateToString(state) + ", backlight=" + backlight);
	}

	mPendingState = state;
	mPendingBacklight = backlight;

	boolean changeInProgress = mStateChangeInProgress \|\| mBacklightChangeInProgress;
	mStateChangeInProgress = stateChanged \|\| mStateChangeInProgress;
	mBacklightChangeInProgress = backlightChanged \|\| mBacklightChangeInProgress;

	if (!changeInProgress) {
	mLock.notifyAll();
	}
	}
	return !mStateChangeInProgress;
	}
	}

	public void dump(PrintWriter pw) {
	synchronized (mLock) {
	pw.println();
	pw.println("Photonic Modulator State:");
	pw.println(" mPendingState=" + Display.stateToString(mPendingState));
	pw.println(" mPendingBacklight=" + mPendingBacklight);
	pw.println(" mActualState=" + Display.stateToString(mActualState));
	pw.println(" mActualBacklight=" + mActualBacklight);
	pw.println(" mStateChangeInProgress=" + mStateChangeInProgress);
	pw.println(" mBacklightChangeInProgress=" + mBacklightChangeInProgress);
	}
	}

	@Override
	public void run() {
	for (;;) {
	// Get pending change.
	final int state;
	final boolean stateChanged;
	final int backlight;
	final boolean backlightChanged;
	synchronized (mLock) {
	state = mPendingState;
	stateChanged = (state != mActualState);
	backlight = mPendingBacklight;
	backlightChanged = (backlight != mActualBacklight);
	if (!stateChanged) {
	// State changed applied, notify outer class.
	postScreenUpdateThreadSafe();
	mStateChangeInProgress = false;
	}
	if (!backlightChanged) {
	mBacklightChangeInProgress = false;
	}
	if (!stateChanged && !backlightChanged) {
	try {
	mLock.wait();
	} catch (InterruptedException ex) { }
	continue;
	}
	mActualState = state;
	mActualBacklight = backlight;
	}

	// Apply pending change.
	if (DEBUG) {
	Slog.d(TAG, "Updating screen state: state="
	+ Display.stateToString(state) + ", backlight=" + backlight);
	}
	mBlanker.requestDisplayState(state, backlight);
	}
	}
	}
	}