[PATCH] drm/amd/display: check fb of primary plane

[Simon Ser]

On Tuesday, March 16th, 2021 at 10:50 PM, Sefa Eyeoglu <contact at scrumplex.net> wrote:

> Sometimes the primary plane might not be initialized (yet), which
> causes dm_check_crtc_cursor to divide by zero.
> Apparently a weird state before a S3-suspend causes the aforementioned
> divide-by-zero error when resuming from S3.  This was explained in
> bug 212293 on Bugzilla.
>
> To avoid this divide-by-zero error we check if the primary plane's fb
> isn't NULL.  If it's NULL the src_w and src_h attributes will be 0,
> which would cause a divide-by-zero.
>
> This fixes Bugzilla report 212293
> https://bugzilla.kernel.org/show_bug.cgi?id=212293
>
> Fixes: 12f4849a1cfd69f3 ("drm/amd/display: check cursor scaling")
> Signed-off-by: Sefa Eyeoglu <contact at scrumplex.net>

Thanks for the fix! In theory we should return -EINVAL here, because we can't
enable the cursor plane without the primary plane. But that would break the
legacy API translation layer in DRM core, which expects that planes can always
be disabled individually.

So this is:

Reviewed-by: Simon Ser <contact at emersion.fr>