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am 5c74bca4: Merge "Synthesize fake vsyncs when the screen is off." into jb-dev

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* commit '5c74bca49a48c3316aca9fed00d287cb8cbc2be4':
  Synthesize fake vsyncs when the screen is off.
This commit is contained in:
Jeff Brown
2012-06-14 21:32:36 -07:00
committed by Android Git Automerger
parent 8607127d8b 5c74bca49a
commit 655410e7b3
1 changed files with 36 additions and 6 deletions
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42
core/java/android/view/Choreographer.java
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@@ -79,6 +79,16 @@ public final class Choreographer {
// be dequeued.
private static final long DEFAULT_FRAME_DELAY = 10;
// The fake vsync delay in milliseconds.
// When the screen is off, we might not receive real vsync pulses from the hardware
// which would cause posted Choreographer callbacks to not run. This is bad because
// messages in the Looper might be blocked behind a barrier that is scheduled to be
// removed by one of those Choreographer callback (see ViewRootImpl.doTraversals).
// Until the barrier is removed, those messages will not run. To prevent starvation
// of the Looper, we synthesize fake vsync pulses at a reduced rate whenever the
// display hardware stops generating them.
private static final long FAKE_VSYNC_DELAY = 100;
// The number of milliseconds between animation frames.
private static volatile long sFrameDelay = DEFAULT_FRAME_DELAY;
@@ -113,6 +123,7 @@ public final class Choreographer {
private static final int MSG_DO_FRAME = 0;
private static final int MSG_DO_SCHEDULE_VSYNC = 1;
private static final int MSG_DO_SCHEDULE_CALLBACK = 2;
private static final int MSG_FAKE_VSYNC = 3;
// All frame callbacks posted by applications have this token.
private static final Object FRAME_CALLBACK_TOKEN = new Object() {
@@ -587,6 +598,13 @@ public final class Choreographer {
private void scheduleVsyncLocked() {
mDisplayEventReceiver.scheduleVsync();
// Post a message to simulate a fake vsync pulse at a reduced rate in case the
// display hardware stops generating them. This ensures that Choreographer
// callbacks can continue to run even if the screen is off.
Message msg = mHandler.obtainMessage(MSG_FAKE_VSYNC);
msg.setAsynchronous(true);
mHandler.sendMessageDelayed(msg, FAKE_VSYNC_DELAY);
}
private boolean isRunningOnLooperThreadLocked() {
@@ -662,6 +680,12 @@ public final class Choreographer {
case MSG_DO_SCHEDULE_CALLBACK:
doScheduleCallback(msg.arg1);
break;
case MSG_FAKE_VSYNC:
if (DEBUG) {
Log.d(TAG, "Handling fake vsync while screen is off.");
}
doFrame(System.nanoTime(), 0);
break;
}
}
}
@@ -683,6 +707,17 @@ public final class Choreographer {
// the message queue. If there are no messages in the queue with timestamps
// earlier than the frame time, then the vsync event will be processed immediately.
// Otherwise, messages that predate the vsync event will be handled first.
if (mHavePendingVsync) {
if (DEBUG) {
Log.d(TAG, "Already have a pending vsync event. There should only be "
+ "one at a time but they can double up when a fake vsync "
+ "is handled in place of a real one.");
}
mHandler.removeCallbacks(this);
} else {
mHavePendingVsync = true;
}
long now = System.nanoTime();
if (timestampNanos > now) {
Log.w(TAG, "Frame time is " + ((timestampNanos - now) * 0.000001f)
@@ -691,12 +726,7 @@ public final class Choreographer {
timestampNanos = now;
}
if (mHavePendingVsync) {
Log.w(TAG, "Already have a pending vsync event. There should only be "
+ "one at a time.");
} else {
mHavePendingVsync = true;
}
mHandler.removeMessages(MSG_FAKE_VSYNC);
mTimestampNanos = timestampNanos;
mFrame = frame;