[PATCH hwc v1] [RFC] drm_hwcomposer: Flatten composition using writeback connector

[Stefan Schake]

Hey Alexandru,

On Tue, Mar 13, 2018 at 5:21 PM, Alexandru Gheorghe
<alexandru-cosmin.gheorghe at arm.com> wrote:
> This patchset tries to add support for using writeback connector to
> flatten a scene when it doesn't change for a while. This idea had
> been floated around on IRC here [1] and here [2].
>
> 2. Heuristic for triggering the flattening.
> I just created a VSyncWorker which will trigger the flattening of the
> scene if it doesn't change for 60 consecutive vsyncs. The countdown
> gets reset every time ValidateDisplay is called. This is a relatively
> basic heuristic, so I'm open to suggestions.

I think when Android deems that the display is sufficiently idle, it will
disable VSync through setVsyncEnabled. Presumably we could just trigger the
flattening on an enabled -> disabled transition?

Thanks,
Stefan