separate transactions from updates

with this changes, SF transactions are handled as soon as possible
but do not trigger updates. the update is delayed until the next
vsync.

this allows us to work much better without requiring triple-buffering.

Change-Id: I1fa10794d0cf742129f0877698b7b1e1f2ec7401

1 files changed, 30 insertions, 9 deletions

diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 9c04d59..64f72d5 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -55,6 +55,7 @@ Layer::Layer(SurfaceFlinger* flinger,
         mCurrentTransform(0),
         mCurrentScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE),
         mCurrentOpacity(true),
+        mRefreshPending(0),
         mFrameLatencyNeeded(false),
         mFrameLatencyOffset(0),
         mFormat(PIXEL_FORMAT_NONE),
@@ -97,12 +98,7 @@ void Layer::onFirstRef()
     mSurfaceTexture = new SurfaceTextureLayer(mTextureName, this);
     mSurfaceTexture->setFrameAvailableListener(new FrameQueuedListener(this));
     mSurfaceTexture->setSynchronousMode(true);
-#ifdef USE_TRIPLE_BUFFERING
-#warning "using triple buffering"
-    mSurfaceTexture->setBufferCountServer(3);
-#else
     mSurfaceTexture->setBufferCountServer(2);
-#endif
 }
 
 Layer::~Layer()
@@ -113,7 +109,7 @@ Layer::~Layer()
 
 void Layer::onFrameQueued() {
     android_atomic_inc(&mQueuedFrames);
-    mFlinger->signalEvent();
+    mFlinger->signalLayerUpdate();
 }
 
 // called with SurfaceFlinger::mStateLock as soon as the layer is entered
@@ -407,16 +403,37 @@ bool Layer::isCropped() const {
 // pageflip handling...
 // ----------------------------------------------------------------------------
 
+bool Layer::onPreComposition()
+{
+    // if there was more than one pending update, request a refresh
+    if (mRefreshPending >= 2) {
+        mRefreshPending = 0;
+        return true;
+    }
+    mRefreshPending = 0;
+    return false;
+}
+
 void Layer::lockPageFlip(bool& recomputeVisibleRegions)
 {
     if (mQueuedFrames > 0) {
+
+        // if we've already called updateTexImage() without going through
+        // a composition step, we have to skip this layer at this point
+        // because we cannot call updateTeximage() without a corresponding
+        // compositionComplete() call.
+        // we'll trigger an update in onPreComposition().
+        if (mRefreshPending++) {
+            return;
+        }
+
         // Capture the old state of the layer for comparisons later
         const bool oldOpacity = isOpaque();
         sp<GraphicBuffer> oldActiveBuffer = mActiveBuffer;
 
         // signal another event if we have more frames pending
         if (android_atomic_dec(&mQueuedFrames) > 1) {
-            mFlinger->signalEvent();
+            mFlinger->signalLayerUpdate();
         }
 
         if (mSurfaceTexture->updateTexImage() < NO_ERROR) {
@@ -519,6 +536,10 @@ void Layer::lockPageFlip(bool& recomputeVisibleRegions)
 void Layer::unlockPageFlip(
         const Transform& planeTransform, Region& outDirtyRegion)
 {
+    if (mRefreshPending >= 2) {
+        return;
+    }
+
     Region dirtyRegion(mPostedDirtyRegion);
     if (!dirtyRegion.isEmpty()) {
         mPostedDirtyRegion.clear();
@@ -552,9 +573,9 @@ void Layer::dump(String8& result, char* buffer, size_t SIZE) const
     snprintf(buffer, SIZE,
             "      "
             "format=%2d, activeBuffer=[%4ux%4u:%4u,%3X],"
-            " transform-hint=0x%02x, queued-frames=%d\n",
+            " transform-hint=0x%02x, queued-frames=%d, mRefreshPending=%d\n",
             mFormat, w0, h0, s0,f0,
-            getTransformHint(), mQueuedFrames);
+            getTransformHint(), mQueuedFrames, mRefreshPending);
 
     result.append(buffer);