BQ: Allow shared buffer to be the first queued buffer

- When single-buffer mode is enabled the shared buffer will now be
  either the first buffer dequeued or the first buffer queued.
  Whichever comes first.

Bug 24940410

Change-Id: I9f7e2630640e37fe1fb967aed41a3025567247a8

2 files changed, 4 insertions, 6 deletions

diff --git a/include/gui/BufferQueueCore.h b/include/gui/BufferQueueCore.h
index acc8c4b07..1b950ab9b 100644
--- a/include/gui/BufferQueueCore.h
+++ b/include/gui/BufferQueueCore.h
@@ -292,9 +292,6 @@ private:
     bool mAsyncMode;
 
     // mSingleBufferMode indicates whether or not single buffer mode is enabled.
-    // In single buffer mode, the last buffer that was dequeued is cached and
-    // returned to all calls to dequeueBuffer and acquireBuffer. This allows the
-    // consumer and producer to access the same buffer simultaneously.
     bool mSingleBufferMode;
 
     // When single buffer mode is enabled, this indicates whether the consumer
diff --git a/include/gui/IGraphicBufferProducer.h b/include/gui/IGraphicBufferProducer.h
index f6b42300a..fee7c6373 100644
--- a/include/gui/IGraphicBufferProducer.h
+++ b/include/gui/IGraphicBufferProducer.h
@@ -526,9 +526,10 @@ public:
 
     // Used to enable/disable single buffer mode.
     //
-    // In single buffer mode the last buffer that was dequeued will be cached
-    // and returned to all calls to dequeueBuffer and acquireBuffer. This allows
-    // the producer and consumer to simultaneously access the same buffer.
+    // When single buffer mode is enabled the first buffer that is queued or
+    // dequeued will be cached and returned to all subsequent calls to
+    // dequeueBuffer and acquireBuffer. This allows the producer and consumer to
+    // simultaneously access the same buffer.
     virtual status_t setSingleBufferMode(bool singleBufferMode) = 0;
 
     // Used to enable/disable auto-refresh.