tree 76d979531ac6ed78cdac7065d4fb70752cbcf0c3
parent 1ce6581ac788eaad58fd3329c2154af7dd74aa3d
author Dan Stoza <stoza@google.com> 1467405218 -0700
committer Dan Stoza <stoza@google.com> 1467823971 -0700

HWC2: Backpressure missed vsyncs into apps

Adds a mechanism to detect whether the prior frame SurfaceFlinger
presented to hardware composer was actually picked up or not. We then
use this mechanism to avoid pushing two frames in the same vsync.
This backpressure is passed back to applications by not latching any
buffers, which will manifest as dequeueBuffer stalling until
SurfaceFlinger releases a buffer on the following vsync.

Also makes the former INVALIDATE_ON_VSYNC behavior the only behavior
so that this functionality works correctly.

Bug: 29413700
Change-Id: Ibde358e45423ee6fea7b5e09ff65e49c4ad67baa