Merge "Don't queue buffer if nothing new to draw in Display"

4 files changed, 45 insertions, 8 deletions

diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/Output.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/Output.h
index fc8dd8be94..38a391b114 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/Output.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/Output.h
@@ -152,6 +152,8 @@ protected:
     virtual const compositionengine::CompositionEngine& getCompositionEngine() const = 0;
     virtual void dumpState(std::string& out) const = 0;
 
+    bool mustRecompose() const;
+
 private:
     void dirtyEntireOutput();
     void updateCompositionStateForBorder(const compositionengine::CompositionRefreshArgs&);
@@ -171,6 +173,9 @@ private:
     std::unique_ptr<ClientCompositionRequestCache> mClientCompositionRequestCache;
     std::unique_ptr<planner::Planner> mPlanner;
     std::unique_ptr<HwcAsyncWorker> mHwComposerAsyncWorker;
+
+    // Whether the content must be recomposed this frame.
+    bool mMustRecompose = false;
 };
 
 // This template factory function standardizes the implementation details of the
diff --git a/services/surfaceflinger/CompositionEngine/src/Display.cpp b/services/surfaceflinger/CompositionEngine/src/Display.cpp
index 09adaed6fc..d359424801 100644
--- a/services/surfaceflinger/CompositionEngine/src/Display.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Display.cpp
@@ -421,7 +421,7 @@ void Display::finishFrame(const compositionengine::CompositionRefreshArgs& refre
     // 1) It is being handled by hardware composer, which may need this to
     //    keep its virtual display state machine in sync, or
     // 2) There is work to be done (the dirty region isn't empty)
-    if (GpuVirtualDisplayId::tryCast(mId) && getDirtyRegion().isEmpty()) {
+    if (GpuVirtualDisplayId::tryCast(mId) && !mustRecompose()) {
         ALOGV("Skipping display composition");
         return;
     }
diff --git a/services/surfaceflinger/CompositionEngine/src/Output.cpp b/services/surfaceflinger/CompositionEngine/src/Output.cpp
index ea78517fac..b5894cf0be 100644
--- a/services/surfaceflinger/CompositionEngine/src/Output.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Output.cpp
@@ -1015,17 +1015,17 @@ void Output::beginFrame() {
     //   frame, then nothing more until we get new layers.
     // - When a display is created with a private layer stack, we won't
     //   emit any black frames until a layer is added to the layer stack.
-    const bool mustRecompose = dirty && !(empty && wasEmpty);
+    mMustRecompose = dirty && !(empty && wasEmpty);
 
     const char flagPrefix[] = {'-', '+'};
     static_cast<void>(flagPrefix);
-    ALOGV_IF("%s: %s composition for %s (%cdirty %cempty %cwasEmpty)", __FUNCTION__,
-             mustRecompose ? "doing" : "skipping", getName().c_str(), flagPrefix[dirty],
-             flagPrefix[empty], flagPrefix[wasEmpty]);
+    ALOGV("%s: %s composition for %s (%cdirty %cempty %cwasEmpty)", __func__,
+          mMustRecompose ? "doing" : "skipping", getName().c_str(), flagPrefix[dirty],
+          flagPrefix[empty], flagPrefix[wasEmpty]);
 
-    mRenderSurface->beginFrame(mustRecompose);
+    mRenderSurface->beginFrame(mMustRecompose);
 
-    if (mustRecompose) {
+    if (mMustRecompose) {
         outputState.lastCompositionHadVisibleLayers = !empty;
     }
 }
@@ -1631,5 +1631,9 @@ void Output::finishPrepareFrame() {
     mRenderSurface->prepareFrame(state.usesClientComposition, state.usesDeviceComposition);
 }
 
+bool Output::mustRecompose() const {
+    return mMustRecompose;
+}
+
 } // namespace impl
 } // namespace android::compositionengine
diff --git a/services/surfaceflinger/CompositionEngine/tests/DisplayTest.cpp b/services/surfaceflinger/CompositionEngine/tests/DisplayTest.cpp
index 51ca213f52..95459c0499 100644
--- a/services/surfaceflinger/CompositionEngine/tests/DisplayTest.cpp
+++ b/services/surfaceflinger/CompositionEngine/tests/DisplayTest.cpp
@@ -971,16 +971,40 @@ TEST_F(DisplayFinishFrameTest, skipsCompositionIfNotDirty) {
 
     // We expect no calls to queueBuffer if composition was skipped.
     EXPECT_CALL(*renderSurface, queueBuffer(_)).Times(0);
+    EXPECT_CALL(*renderSurface, beginFrame(false));
 
     gpuDisplay->editState().isEnabled = true;
     gpuDisplay->editState().usesClientComposition = false;
     gpuDisplay->editState().layerStackSpace.setContent(Rect(0, 0, 1, 1));
     gpuDisplay->editState().dirtyRegion = Region::INVALID_REGION;
+    gpuDisplay->editState().lastCompositionHadVisibleLayers = true;
 
+    gpuDisplay->beginFrame();
     gpuDisplay->finishFrame({}, std::move(mResultWithoutBuffer));
 }
 
-TEST_F(DisplayFinishFrameTest, performsCompositionIfDirty) {
+TEST_F(DisplayFinishFrameTest, skipsCompositionIfEmpty) {
+    auto args = getDisplayCreationArgsForGpuVirtualDisplay();
+    std::shared_ptr<impl::Display> gpuDisplay = impl::createDisplay(mCompositionEngine, args);
+
+    mock::RenderSurface* renderSurface = new StrictMock<mock::RenderSurface>();
+    gpuDisplay->setRenderSurfaceForTest(std::unique_ptr<RenderSurface>(renderSurface));
+
+    // We expect no calls to queueBuffer if composition was skipped.
+    EXPECT_CALL(*renderSurface, queueBuffer(_)).Times(0);
+    EXPECT_CALL(*renderSurface, beginFrame(false));
+
+    gpuDisplay->editState().isEnabled = true;
+    gpuDisplay->editState().usesClientComposition = false;
+    gpuDisplay->editState().layerStackSpace.setContent(Rect(0, 0, 1, 1));
+    gpuDisplay->editState().dirtyRegion = Region(Rect(0, 0, 1, 1));
+    gpuDisplay->editState().lastCompositionHadVisibleLayers = false;
+
+    gpuDisplay->beginFrame();
+    gpuDisplay->finishFrame({}, std::move(mResultWithoutBuffer));
+}
+
+TEST_F(DisplayFinishFrameTest, performsCompositionIfDirtyAndNotEmpty) {
     auto args = getDisplayCreationArgsForGpuVirtualDisplay();
     std::shared_ptr<impl::Display> gpuDisplay = impl::createDisplay(mCompositionEngine, args);
 
@@ -989,11 +1013,15 @@ TEST_F(DisplayFinishFrameTest, performsCompositionIfDirty) {
 
     // We expect a single call to queueBuffer when composition is not skipped.
     EXPECT_CALL(*renderSurface, queueBuffer(_)).Times(1);
+    EXPECT_CALL(*renderSurface, beginFrame(true));
 
     gpuDisplay->editState().isEnabled = true;
     gpuDisplay->editState().usesClientComposition = false;
     gpuDisplay->editState().layerStackSpace.setContent(Rect(0, 0, 1, 1));
     gpuDisplay->editState().dirtyRegion = Region(Rect(0, 0, 1, 1));
+    gpuDisplay->editState().lastCompositionHadVisibleLayers = true;
+
+    gpuDisplay->beginFrame();
     gpuDisplay->finishFrame({}, std::move(mResultWithBuffer));
 }