SurfaceFlinger: Fix PTS on stale buffers
SurfaceFlinger's (Layer's) shadow copy of the BufferQueue queue was
getting out of sync for a few reasons. This change fixes these by
doing the following:
- Adds a check to re-synchronize the shadow copy every time we
successfully acquire a buffer by first dropping stale buffers before
removing the current buffer.
- Avoids trying to perform updates for buffers which have been rejected
(for incorrect dimensions) by SurfaceFlinger.
- Adds IGraphicBufferConsumer::setShadowQueueSize, which allows the
consumer to notify the BufferQueue that it is maintaining a shadow
copy of the queue and prevents it from dropping so many buffers
during acquireBuffer that it ends up returning a buffer for which the
consumer has not yet received an onFrameAvailable call.
Bug: 20096136
Change-Id: I78d0738428005fc19b3be85cc8f1db498043612f
(cherry picked from commit 2e36f2283f48ab764b496490c73a132acf21df3a)
diff --git a/libs/gui/BufferQueueConsumer.cpp b/libs/gui/BufferQueueConsumer.cpp
index c7d5e00..2deef0e 100644
--- a/libs/gui/BufferQueueConsumer.cpp
+++ b/libs/gui/BufferQueueConsumer.cpp
@@ -89,7 +89,20 @@
// the timestamps are being auto-generated by Surface. If the app isn't
// generating timestamps explicitly, it probably doesn't want frames to
// be discarded based on them.
+ //
+ // If the consumer is shadowing our queue, we also make sure that we
+ // don't drop so many buffers that the consumer hasn't received the
+ // onFrameAvailable callback for the buffer it acquires. That is, we
+ // want the buffer we return to be in the consumer's shadow queue.
+ size_t droppableBuffers = mCore->mConsumerShadowQueueSize > 1 ?
+ mCore->mConsumerShadowQueueSize - 1 : 0;
while (mCore->mQueue.size() > 1 && !mCore->mQueue[0].mIsAutoTimestamp) {
+ if (mCore->mConsumerHasShadowQueue && droppableBuffers == 0) {
+ BQ_LOGV("acquireBuffer: no droppable buffers in consumer's"
+ " shadow queue, continuing");
+ break;
+ }
+
// If entry[1] is timely, drop entry[0] (and repeat). We apply an
// additional criterion here: we only drop the earlier buffer if our
// desiredPresent falls within +/- 1 second of the expected present.
@@ -124,6 +137,7 @@
}
mCore->mQueue.erase(front);
front = mCore->mQueue.begin();
+ --droppableBuffers;
}
// See if the front buffer is due
@@ -537,6 +551,14 @@
return mCore->mSidebandStream;
}
+void BufferQueueConsumer::setShadowQueueSize(size_t size) {
+ ATRACE_CALL();
+ BQ_LOGV("setShadowQueueSize: %zu", size);
+ Mutex::Autolock lock(mCore->mMutex);
+ mCore->mConsumerHasShadowQueue = true;
+ mCore->mConsumerShadowQueueSize = size;
+}
+
void BufferQueueConsumer::dump(String8& result, const char* prefix) const {
mCore->dump(result, prefix);
}