[PATCH] drm/vc4: Add support for plane alpha

[Stefan Schake]

On Sat, Apr 21, 2018 at 1:45 AM, Eric Anholt <eric at anholt.net> wrote:
> Stefan Schake <stschake at gmail.com> writes:
>
>> The HVS supports mixing fixed alpha with per-pixel alpha or
>> setting a fixed plane alpha in case there is no per-pixel information.
>> This allows us to support the generic DRM plane alpha property.
>
> Don't we need to set needs_bg_fill based on alpha != OPAQUE, as well?
>
> Other than that, looks good to me.

I did forget about the whole background situation, and a quick test
shows you are right: anything less than opaque has the funky
repeating pattern artifact.

Thanks, I'll send a new version.