tree 76b185d252b95b05e8d74e7a1644b843f8839725
parent a4eb91da03bd785bc91bed0d25a9efaa9baba1c1
author Mathias Agopian <mathias@google.com> 1252366365 -0700
committer Mathias Agopian <mathias@google.com> 1252366365 -0700

fix [2068105] implement queueBuffer/lockBuffer/dequeueBuffer properly

Rewrote SurfaceFlinger's buffer management from the ground-up.
The design now support an arbitrary number of buffers per surface, however the current implementation is limited to four. Currently only 2 buffers are used in practice.

The main new feature is to be able to dequeue all buffers at once (very important when there are only two). 

A client can dequeue all buffers until there are none available, it can lock all buffers except the last one that is used for composition. The client will block then, until a new buffer is enqueued.

The current implementation requires that buffers are locked in the same order they are dequeued and enqueued in the same order they are locked. Only one buffer can be locked at a time.

eg. Allowed sequence:   DQ, DQ, LOCK, Q, LOCK, Q
eg. Forbidden sequence: DQ, DQ, LOCK, LOCK, Q, Q