Le lun. 29 mars 2021 à 17:35, Maxime Ripard <maxime@xxxxxxxxxx> a
écrit :
On Mon, Mar 29, 2021 at 04:15:28PM +0100, Paul Cercueil wrote:
Hi Maxime,
Le lun. 29 mars 2021 à 16:07, Maxime Ripard <maxime@xxxxxxxxxx> a
écrit :
> On Sat, Mar 27, 2021 at 11:22:14AM +0000, Paul Cercueil wrote:
> > The ingenic-drm driver has two mutually exclusive primary
planes
> > already; so the fact that a CRTC must have one and only one
primary
> > plane is an invalid assumption.
>
> I mean, no? It's been documented for a while that a CRTC should
only
> have a single primary, so I'd say that the invalid assumption was
that
> it was possible to have multiple primary planes for a CRTC.
Documented where?
I did read the doc of "enum drm_plane_type" in <drm/drm_plane.h>,
and the
DRM_PLANE_TYPE_PRIMARY describes my two planes, so I went with that.
At least since 4.9, this was in the documentation generated for DRM:
https://elixir.bootlin.com/linux/v4.9.263/source/drivers/gpu/drm/drm_plane.c#L43
Ok, I read that as "all drivers should provide AT LEAST one primary
plane per CRTC", and not as "all drivers should provide ONE AND ONLY
ONE primary plane per CRTC". My bad.
-Paul
