commit 3249fb6a0d8dd1e2020884711ce7d078b913ee44
author Sungtak Lee <taklee@google.com> Sat Mar 02 16:40:47 2019 -0800
committer Sungtak Lee <taklee@google.com> Tue Apr 09 10:39:07 2019 -0700
tree 30a1930e18425a84dea19867fe3656e79a9b0205
parent 3c9aec6db94841a5b16075923d22b38423dfa667

BufferQueueProducer::queueBuffer may not drop buffers

Enable BufferQueueProducer::setDequeueTimeout retain existing
dropping behavior. Setting negative and zero to setDequeueTimeout will
not change existing dropping behavior.

BufferQueueProducer::setLegacyBufferDrop can disable buffer dropping
behavior of BufferQueueProducer::queueBuffer. If it's disabled, buffers
will not be dropped unless consumer is SurfaceFlinger.

Bug: 130039639
Change-Id: I8432a7ad386836498e632c67953ad49c6be008bb

libs/gui/BufferQueueProducer.cpp

diff --git a/libs/gui/BufferQueueProducer.cpp b/libs/gui/BufferQueueProducer.cpp
index 72ae375..4ff69c5 100644
--- a/libs/gui/BufferQueueProducer.cpp
+++ b/libs/gui/BufferQueueProducer.cpp
@@ -889,7 +889,8 @@
         item.mFence = acquireFence;
         item.mFenceTime = acquireFenceTime;
         item.mIsDroppable = mCore->mAsyncMode ||
-                mCore->mDequeueBufferCannotBlock ||
+                (!mCore->mLegacyBufferDrop && mConsumerIsSurfaceFlinger) ||
+                (mCore->mLegacyBufferDrop && mCore->mQueueBufferCanDrop) ||
                 (mCore->mSharedBufferMode && mCore->mSharedBufferSlot == slot);
         item.mSurfaceDamage = surfaceDamage;
         item.mQueuedBuffer = true;
@@ -1230,9 +1231,11 @@
     mCore->mConnectedPid = BufferQueueThreadState::getCallingPid();
     mCore->mBufferHasBeenQueued = false;
     mCore->mDequeueBufferCannotBlock = false;
-    if (mDequeueTimeout < 0) {
-        mCore->mDequeueBufferCannotBlock =
-                mCore->mConsumerControlledByApp && producerControlledByApp;
+    mCore->mQueueBufferCanDrop = false;
+    mCore->mLegacyBufferDrop = true;
+    if (mCore->mConsumerControlledByApp && producerControlledByApp) {
+        mCore->mDequeueBufferCannotBlock = mDequeueTimeout < 0;
+        mCore->mQueueBufferCanDrop = mDequeueTimeout <= 0;
     }
 
     mCore->mAllowAllocation = true;
@@ -1516,12 +1519,26 @@
     }
 
     mDequeueTimeout = timeout;
-    mCore->mDequeueBufferCannotBlock = false;
+    if (timeout >= 0) {
+        mCore->mDequeueBufferCannotBlock = false;
+        if (timeout != 0) {
+            mCore->mQueueBufferCanDrop = false;
+        }
+    }
 
     VALIDATE_CONSISTENCY();
     return NO_ERROR;
 }
 
+status_t BufferQueueProducer::setLegacyBufferDrop(bool drop) {
+    ATRACE_CALL();
+    BQ_LOGV("setLegacyBufferDrop: drop = %d", drop);
+
+    std::lock_guard<std::mutex> lock(mCore->mMutex);
+    mCore->mLegacyBufferDrop = drop;
+    return NO_ERROR;
+}
+
 status_t BufferQueueProducer::getLastQueuedBuffer(sp<GraphicBuffer>* outBuffer,
         sp<Fence>* outFence, float outTransformMatrix[16]) {
     ATRACE_CALL();