Merge "SurfaceView: positionLost locking fix" into rvc-dev am: bff3812e82 (30782216) · Commits · e / os / android_frameworks_base

core/java/android/view/SurfaceView.java

+28 −7

Original line number	Diff line number	Diff line
		@@ -134,6 +134,23 @@ public class SurfaceView extends View implements ViewRootImpl.SurfaceChangedCall
		// we need to preserve the old one until the new one has drawn.
		SurfaceControl mDeferredDestroySurfaceControl;
		SurfaceControl mBackgroundControl;

		/**
		* We use this lock in SOME cases when reading or writing SurfaceControl,
		* but use the following model so that the RenderThread can run locklessly
		* in the position up-date case.
		*
		* 1. UI Thread can read from mSurfaceControl (use in Transactions) without
		* holding the lock.
		* 2. UI Thread will hold the lock when writing to mSurfaceControl (calling release
		* or remove).
		* 3. Render thread will also hold the lock when writing to mSurfaceControl (e.g.
		* calling release from positionLost).
		* 3. RenderNode.PositionUpdateListener::positionChanged will only be called
		* when the UI thread is paused (blocked on the Render thread).
		* 4. positionChanged thus will not be required to hold the lock as the
		* UI thread is blocked, and the other writer is the RT itself.
		*/
		final Object mSurfaceControlLock = new Object();
		final Rect mTmpRect = new Rect();

		@@ -1297,6 +1314,11 @@ public class SurfaceView extends View implements ViewRootImpl.SurfaceChangedCall
		(viewRoot != null ? viewRoot.getBLASTSyncTransaction() : mRtTransaction) :
		mRtTransaction;

		/**
		* positionLost can be called while UI thread is un-paused so we
		* need to hold the lock here.
		*/
		synchronized (mSurfaceControlLock) {
		if (frameNumber > 0 && viewRoot != null && !useBLAST) {
		if (viewRoot.mSurface.isValid()) {
		mRtTransaction.deferTransactionUntil(mSurfaceControl,
		@@ -1305,7 +1327,6 @@ public class SurfaceView extends View implements ViewRootImpl.SurfaceChangedCall
		}
		t.hide(mSurfaceControl);

		synchronized (mSurfaceControlLock) {
		if (mRtReleaseSurfaces) {
		mRtReleaseSurfaces = false;
		mRtTransaction.remove(mSurfaceControl);