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

[Liu, Zhan]

[AMD Official Use Only - Internal Distribution Only]

+ Ville

On Sat, Jan 2, 2021 at 4:31 PM Mario Kleiner <mario.kleiner.de at gmail.com> wrote:
>
> On Sat, Jan 2, 2021 at 3:02 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>
> > Fixes: 816853f9dc40 ("drm/amd/display: Set new format info for converted metadata.")
> > ---
> >  drivers/gpu/drm/drm_plane.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/drm_plane.c b/drivers/gpu/drm/drm_plane.c
> > index e6231947f987..f5085990cfac 100644
> > --- a/drivers/gpu/drm/drm_plane.c
> > +++ b/drivers/gpu/drm/drm_plane.c
> > @@ -1163,7 +1163,7 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
> >         if (ret)
> >                 goto out;
> >
> > -       if (old_fb->format != fb->format) {
> > +       if (old_fb->format->format != fb->format->format) {
>

I agree with this patch, though considering the original way was made by Ville, I will wait for Ville's input first. Adding my "Acked-by" here.

This patch is:
Acked-by: Zhan Liu <zhan.liu at amd.com>

> This was btw. the original way before Ville made it more strict about
> 4 years ago, to catch issues related to tiling, and more complex
> layouts, like the dcc tiling/retiling introduced by your modifier
> patches. That's why I hope my alternative patch is a good solution for
> atomic drivers while keeping the strictness for potential legacy
> drivers.
>
> -mario
>
> >                 DRM_DEBUG_KMS("Page flip is not allowed to change frame buffer format.\n");
> >                 ret = -EINVAL;
> >                 goto out;
> > --
> > 2.29.2
> >