/*
* 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.power;
import com.android.server.LightsService;
import android.os.AsyncTask;
import android.os.Handler;
import android.os.Looper;
import android.os.PowerManager;
import android.util.FloatProperty;
import android.util.IntProperty;
import android.util.Slog;
import android.view.Choreographer;
import java.io.PrintWriter;
/**
* Controls the display power state.
* <p>
* This component is similar in nature to a {@link 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
* {@link PowerManagerService} 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 final Handler mHandler;
private final Choreographer mChoreographer;
private final ElectronBeam mElectronBeam;
private final DisplayBlanker mDisplayBlanker;
private final LightsService.Light mBacklight;
private final PhotonicModulator mPhotonicModulator;
private boolean mScreenOn;
private int mScreenBrightness;
private boolean mScreenReady;
private boolean mScreenUpdatePending;
private boolean mElectronBeamPrepared;
private float mElectronBeamLevel;
private boolean mElectronBeamReady;
private boolean mElectronBeamDrawPending;
private Runnable mCleanListener;
public DisplayPowerState(ElectronBeam electronBean,
DisplayBlanker displayBlanker, LightsService.Light backlight) {
mHandler = new Handler(true /*async*/);
mChoreographer = Choreographer.getInstance();
mElectronBeam = electronBean;
mDisplayBlanker = displayBlanker;
mBacklight = backlight;
mPhotonicModulator = new PhotonicModulator();
// 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.
mScreenOn = true;
mScreenBrightness = PowerManager.BRIGHTNESS_ON;
scheduleScreenUpdate();
mElectronBeamPrepared = false;
mElectronBeamLevel = 1.0f;
mElectronBeamReady = true;
}
public static final FloatProperty<DisplayPowerState> ELECTRON_BEAM_LEVEL =
new FloatProperty<DisplayPowerState>("electronBeamLevel") {
@Override
public void setValue(DisplayPowerState object, float value) {
object.setElectronBeamLevel(value);
}
@Override
public Float get(DisplayPowerState object) {
return object.getElectronBeamLevel();
}
};
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 or off.
*/
public void setScreenOn(boolean on) {
if (mScreenOn != on) {
if (DEBUG) {
Slog.d(TAG, "setScreenOn: on=" + on);
}
mScreenOn = on;
mScreenReady = false;
scheduleScreenUpdate();
}
}
/**
* Returns true if the screen is on.
*/
public boolean isScreenOn() {
return mScreenOn;
}
/**
* 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 (mScreenOn) {
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 prepareElectronBeam(int mode) {
if (!mElectronBeam.prepare(mode)) {
mElectronBeamPrepared = false;
mElectronBeamReady = true;
return false;
}
mElectronBeamPrepared = true;
mElectronBeamReady = false;
scheduleElectronBeamDraw();
return true;
}
/**
* Dismisses the electron beam surface.
*/
public void dismissElectronBeam() {
mElectronBeam.dismiss();
mElectronBeamPrepared = false;
mElectronBeamReady = true;
}
/**
* 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 setElectronBeamLevel(float level) {
if (mElectronBeamLevel != level) {
if (DEBUG) {
Slog.d(TAG, "setElectronBeamLevel: level=" + level);
}
mElectronBeamLevel = level;
if (mScreenOn) {
mScreenReady = false;
scheduleScreenUpdate(); // update backlight brightness
}
if (mElectronBeamPrepared) {
mElectronBeamReady = false;
scheduleElectronBeamDraw();
}
}
}
/**
* Gets the level of the electron beam steering current.
*/
public float getElectronBeamLevel() {
return mElectronBeamLevel;
}
/**
* 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 || !mElectronBeamReady) {
mCleanListener = listener;
return false;
} else {
mCleanListener = null;
return true;
}
}
public void dump(PrintWriter pw) {
pw.println();
pw.println("Display Power State:");
pw.println(" mScreenOn=" + mScreenOn);
pw.println(" mScreenBrightness=" + mScreenBrightness);
pw.println(" mScreenReady=" + mScreenReady);
pw.println(" mScreenUpdatePending=" + mScreenUpdatePending);
pw.println(" mElectronBeamPrepared=" + mElectronBeamPrepared);
pw.println(" mElectronBeamLevel=" + mElectronBeamLevel);
pw.println(" mElectronBeamReady=" + mElectronBeamReady);
pw.println(" mElectronBeamDrawPending=" + mElectronBeamDrawPending);
mPhotonicModulator.dump(pw);
mElectronBeam.dump(pw);
}
private void scheduleScreenUpdate() {
if (!mScreenUpdatePending) {
mScreenUpdatePending = true;
postScreenUpdateThreadSafe();
}
}
private void postScreenUpdateThreadSafe() {
mHandler.removeCallbacks(mScreenUpdateRunnable);
mHandler.post(mScreenUpdateRunnable);
}
private void scheduleElectronBeamDraw() {
if (!mElectronBeamDrawPending) {
mElectronBeamDrawPending = true;
mChoreographer.postCallback(Choreographer.CALLBACK_TRAVERSAL,
mElectronBeamDrawRunnable, null);
}
}
private void invokeCleanListenerIfNeeded() {
final Runnable listener = mCleanListener;
if (listener != null && mScreenReady && mElectronBeamReady) {
mCleanListener = null;
listener.run();
}
}
private final Runnable mScreenUpdateRunnable = new Runnable() {
@Override
public void run() {
mScreenUpdatePending = false;
int brightness = mScreenOn && mElectronBeamLevel > 0f ? mScreenBrightness : 0;
if (mPhotonicModulator.setState(mScreenOn, brightness)) {
mScreenReady = true;
invokeCleanListenerIfNeeded();
}
}
};
private final Runnable mElectronBeamDrawRunnable = new Runnable() {
@Override
public void run() {
mElectronBeamDrawPending = false;
if (mElectronBeamPrepared) {
mElectronBeam.draw(mElectronBeamLevel);
}
mElectronBeamReady = true;
invokeCleanListenerIfNeeded();
}
};
/**
* Updates the state of the screen and backlight asynchronously on a separate thread.
*/
private final class PhotonicModulator {
private static final boolean INITIAL_SCREEN_ON = false; // unknown, assume off
private static final int INITIAL_BACKLIGHT = -1; // unknown
private final Object mLock = new Object();
private boolean mPendingOn = INITIAL_SCREEN_ON;
private int mPendingBacklight = INITIAL_BACKLIGHT;
private boolean mActualOn = INITIAL_SCREEN_ON;
private int mActualBacklight = INITIAL_BACKLIGHT;
private boolean mChangeInProgress;
public boolean setState(boolean on, int backlight) {
synchronized (mLock) {
if (on != mPendingOn || backlight != mPendingBacklight) {
if (DEBUG) {
Slog.d(TAG, "Requesting new screen state: on=" + on
+ ", backlight=" + backlight);
}
mPendingOn = on;
mPendingBacklight = backlight;
if (!mChangeInProgress) {
mChangeInProgress = true;
AsyncTask.THREAD_POOL_EXECUTOR.execute(mTask);
}
}
return mChangeInProgress;
}
}
public void dump(PrintWriter pw) {
pw.println();
pw.println("Photonic Modulator State:");
pw.println(" mPendingOn=" + mPendingOn);
pw.println(" mPendingBacklight=" + mPendingBacklight);
pw.println(" mActualOn=" + mActualOn);
pw.println(" mActualBacklight=" + mActualBacklight);
pw.println(" mChangeInProgress=" + mChangeInProgress);
}
private final Runnable mTask = new Runnable() {
@Override
public void run() {
// Apply pending changes until done.
for (;;) {
final boolean on;
final boolean onChanged;
final int backlight;
final boolean backlightChanged;
synchronized (mLock) {
on = mPendingOn;
onChanged = (on != mActualOn);
backlight = mPendingBacklight;
backlightChanged = (backlight != mActualBacklight);
if (!onChanged && !backlightChanged) {
mChangeInProgress = false;
break;
}
mActualOn = on;
mActualBacklight = backlight;
}
if (DEBUG) {
Slog.d(TAG, "Updating screen state: on=" + on
+ ", backlight=" + backlight);
}
if (onChanged && on) {
mDisplayBlanker.unblankAllDisplays();
}
if (backlightChanged) {
mBacklight.setBrightness(backlight);
}
if (onChanged && !on) {
mDisplayBlanker.blankAllDisplays();
}
}
// Let the outer class know that all changes have been applied.
postScreenUpdateThreadSafe();
}
};
}
}