[PATCH v2] drm: Check actual format for legacy pageflip.

[Bas Nieuwenhuizen]

On Mon, Jan 11, 2021 at 4:02 PM Alex Deucher <alexdeucher at gmail.com> wrote:
>
> On Sat, Jan 9, 2021 at 9:11 PM Bas Nieuwenhuizen
> <bas at basnieuwenhuizen.nl> wrote:
> >
> > With modifiers one can actually have different format_info structs
> > for the same format, which now matters for AMDGPU since we convert
> > implicit modifiers to explicit modifiers with multiple planes.
> >
> > I checked other drivers and it doesn't look like they end up triggering
> > this case so I think this is safe to relax.
> >
> > Signed-off-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl>
> > Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> > Reviewed-by: Zhan Liu <zhan.liu at amd.com>
> > Acked-by: Christian König <christian.koenig at amd.com>
> > Acked-by: Alex Deucher <alexander.deucher at amd.com>
> > Fixes: 816853f9dc40 ("drm/amd/display: Set new format info for converted metadata.")
>
> Do you have commit rights to drm-misc or do you need someone to commit
> this for you?

I don't have commit rights so if the patch could be committed for me
that would be appreciated!
>
> Thanks!
>
> Alex
>
> > ---
> >  drivers/gpu/drm/drm_plane.c | 9 ++++++++-
> >  1 file changed, 8 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
> > index e6231947f987..a0cb746bcb0a 100644
> > --- a/drivers/gpu/drm/drm_plane.c
> > +++ b/drivers/gpu/drm/drm_plane.c
> > @@ -1163,7 +1163,14 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
> >         if (ret)
> >                 goto out;
> >
> > -       if (old_fb->format != fb->format) {
> > +       /*
> > +        * Only check the FOURCC format code, excluding modifiers. This is
> > +        * enough for all legacy drivers. Atomic drivers have their own
> > +        * checks in their ->atomic_check implementation, which will
> > +        * return -EINVAL if any hw or driver constraint is violated due
> > +        * to modifier changes.
> > +        */
> > +       if (old_fb->format->format != fb->format->format) {
> >                 DRM_DEBUG_KMS("Page flip is not allowed to change frame buffer format.\n");
> >                 ret = -EINVAL;
> >                 goto out;
> > --
> > 2.29.2
> >
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> > amd-gfx at lists.freedesktop.org
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