hwc: Include more cases in partial MDP composition.
When MDP cannot support a layer, we send the whole list of layers to
GPU. If such layers are not updating they can be cached on FB while
allowing the rest to take the MDP route.
Example # 1: Volume bar on video in 90 rotated mode. Since volume bar
is not h/w accelerated, there is no prerotation and we invoke the GPU
for redraws each round. With this change we won't because of caching.
Example # 2: If prerotation is applied to layers on primary, the
secondary layers would show a transform and the whole list is redrawn
with GPU. Now we could make use of caching.
This change also imposes a 1 layer limit on secondary, but now allows
full and partial MDP comp, thus benefiting secondary-only content.
Change-Id: I7eb43ba817f1081f317fefa99fa0c507344060e8
3 files changed