tree 13505e6bd5702430e77a34d668079d820a2cfcc9
parent 84a0b9238af5c138331193bf9cba55fed1eab618
author Mike Stroyan <stroyan@google.com> 1492711848 -0600
committer Mike Stroyan <stroyan@google.com> 1492785330 -0600

Defer surfaceflinger composition until data latch

If layer data is not yet ready, latchBuffer will return an empty region.
SurfaceFlinger::handlePageFlip will now check if any layer has a queued
frame which succeeded in latching data.
If no new frame is latched, handlePageFlip will return false.
That will defer refresh until the next vsync.
That reduces HWC and GPU load, improving framerates.
It prevents dEQP tests from timing out on some devices.

Test: dEQP-VK.wsi.android.incremental_present.scale_down.fifo.reference
Bug: 37439915
Change-Id: Id46c82f79953f3a147af77bb0e8e81a395c606b3