[Intel-gfx] [PATCH] drm/i915/display: Check source height is > 0

[Teres Alexis, Alan Previn]

Is there a better place for this check higher up the intel specific atomic-check? (so the check won't be skl specific - i notice that intel_adjusted_rate is also called by
ilk_foo as well and non-backend-specific functions). Else, perhaps intel_adjusted_rate should add a check + WARN? (if we are trying to propagate this slowly across HW).


...alan 

On Mon, 2022-12-26 at 22:53 -0700, Drew Davenport wrote:
> The error message suggests that the height of the src rect must be at
> least 1. Reject source with height of 0.
> 
> Signed-off-by: Drew Davenport <ddavenport at chromium.org>
> 
> ---
> I was investigating some divide-by-zero crash reports on ChromeOS which
> pointed to the intel_adjusted_rate function. Further prodding showed
> that I could reproduce this in a simple test program if I made src_h
> some value less than 1 but greater than 0.
> 
> This seemed to be a sensible place to check that the source height is at
> least 1. I tried to repro this issue on an amd device I had on hand, and
> the configuration was rejected.
> 
> Would it make sense to add a check that source dimensions are at least 1
> somewhere in core, like in drm_atomic_plane_check? Or is that a valid
> use case on some devices, and thus any such check should be done on a
> per-driver basis?
> 
> Thanks.
> 
>  drivers/gpu/drm/i915/display/skl_universal_plane.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/skl_universal_plane.c b/drivers/gpu/drm/i915/display/skl_universal_plane.c
> index 4b79c2d2d6177..9b172a1e90deb 100644
> --- a/drivers/gpu/drm/i915/display/skl_universal_plane.c
> +++ b/drivers/gpu/drm/i915/display/skl_universal_plane.c
> @@ -1627,7 +1627,7 @@ static int skl_check_main_surface(struct intel_plane_state *plane_state)
>  	u32 offset;
>  	int ret;
>  
> -	if (w > max_width || w < min_width || h > max_height) {
> +	if (w > max_width || w < min_width || h > max_height || h < 1) {
>  		drm_dbg_kms(&dev_priv->drm,
>  			    "requested Y/RGB source size %dx%d outside limits (min: %dx1 max: %dx%d)\n",
>  			    w, h, min_width, max_width, max_height);
> -- 
> 2.39.0.314.g84b9a713c41-goog
>