Enable backpressure for BufferStateLayer

The default behaviour of buffer state layer is to drop older
buffers if there are newer buffers that are ready to be presented.

When emulating BufferQueue behavior via the adapter, we want
to queue up buffers without any present timestamps. To solve this,
we introduce a layer state flag to keep the buffer in the transaction
queue if there is already a buffer that is ready to be applied.

Test: atest SurfaceViewBufferTests:BufferPresentationTests
Bug: 176967609
Change-Id: I33f6347bd1c7a2d80dc4214e596bb864abe8c6bf

1 files changed, 1 insertions, 1 deletions

diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index 66ce3f1a44..177a81a7bc 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -1312,7 +1312,7 @@ bool Layer::setBlurRegions(const std::vector<BlurRegion>& blurRegions) {
     return true;
 }
 
-bool Layer::setFlags(uint8_t flags, uint8_t mask) {
+bool Layer::setFlags(uint32_t flags, uint32_t mask) {
     const uint32_t newFlags = (mCurrentState.flags & ~mask) | (flags & mask);
     if (mCurrentState.flags == newFlags) return false;
     mCurrentState.sequence++;