Re: [PATCH AUTOSEL 5.4 13/15] drm/amdgpu/dc: Require primary plane to be enabled whenever the CRTC is

[Sasha Levin]

On Mon, Sep 21, 2020 at 04:48:05PM +0200, Michel Dänzer wrote:
> On 2020-09-21 4:40 p.m., Sasha Levin wrote:
> > From: Michel Dänzer <mdaenzer@xxxxxxxxxx>
> >
> > [ Upstream commit 2f228aab21bbc74e90e267a721215ec8be51daf7 ]
> >
> > Don't check drm_crtc_state::active for this either, per its
> > documentation in include/drm/drm_crtc.h:
> >
> >  * Hence drivers must not consult @active in their various
> >  * &drm_mode_config_funcs.atomic_check callback to reject an atomic
> >  * commit.
> >
> > atomic_remove_fb disables the CRTC as needed for disabling the primary
> > plane.
> >
> > This prevents at least the following problems if the primary plane gets
> > disabled (e.g. due to destroying the FB assigned to the primary plane,
> > as happens e.g. with mutter in Wayland mode):
> >
> > * The legacy cursor ioctl returned EINVAL for a non-0 cursor FB ID
> >   (which enables the cursor plane).
> > * If the cursor plane was enabled, changing the legacy DPMS property
> >   value from off to on returned EINVAL.
> >
> > v2:
> > * Minor changes to code comment and commit log, per review feedback.
> >
> > GitLab: https://gitlab.gnome.org/GNOME/mutter/-/issues/1108
> > GitLab: https://gitlab.gnome.org/GNOME/mutter/-/issues/1165
> > GitLab: https://gitlab.gnome.org/GNOME/mutter/-/issues/1344
> > Suggested-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> > Acked-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> > Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx>
> > Signed-off-by: Michel Dänzer <mdaenzer@xxxxxxxxxx>
> > Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
>
> I'm a bit nervous about this getting backported so far back so 
> quickly. I'd prefer waiting for 5.9 final first at least.

Will drop it for now, thanks.

--
Thanks,
Sasha