Re: [PATCH v2 09/12] drm/sun4i: backend: Add a custom atomic_check for the frontend
From: Chen-Yu Tsai
Date: Thu Jan 04 2018 - 10:49:31 EST
On Mon, Dec 18, 2017 at 10:57 PM, Maxime Ripard
<maxime.ripard@xxxxxxxxxxxxxxxxxx> wrote:
> Now that we have everything in place, we can start enabling the frontend.
> This is more difficult than one would assume since there can only be one
> plane using the frontend per-backend.
>
> We therefore need to make sure that the userspace will not try to setup
> multiple planes using it, since that would be impossible. In order to
> prevent that, we can create an atomic_check callback that will check that
> only one plane will effectively make use of the frontend in a given
> configuration, and will toggle the switch in that plane state so that the
> proper setup function can do their role.
>
> Reviewed-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Chen-Yu Tsai <wens@xxxxxxxx>