[RFC PATCH v3 01/23] drm: Don't treat 0 as -1 in drm_fixp2int_ceil

Melissa Wen mwen at igalia.com
Wed Dec 6 12:05:43 UTC 2023


On 11/08, Harry Wentland wrote:
> Unit testing this in VKMS shows that passing 0 into
> this function returns -1, which is highly counter-
> intuitive. Fix it by checking whether the input is
> >= 0 instead of > 0.
> 
Nice finding. Thanks!

Could you add the fixes tag? AFAIU, this one:

Fixes: 64566b5e767f9 ("drm: Add drm_fixp_from_fraction and drm_fixp2int_ceil")
Reviewed-by: Melissa Wen <mwen at igalia.com>

> Signed-off-by: Harry Wentland <harry.wentland at amd.com>
> Reviewed-by: Simon Ser <contact at emersion.fr>
> ---
>  include/drm/drm_fixed.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/drm/drm_fixed.h b/include/drm/drm_fixed.h
> index 6ea339d5de08..0c9f917a4d4b 100644
> --- a/include/drm/drm_fixed.h
> +++ b/include/drm/drm_fixed.h
> @@ -95,7 +95,7 @@ static inline int drm_fixp2int_round(s64 a)
>  
>  static inline int drm_fixp2int_ceil(s64 a)
>  {
> -	if (a > 0)
> +	if (a >= 0)
>  		return drm_fixp2int(a + DRM_FIXED_ALMOST_ONE);
>  	else
>  		return drm_fixp2int(a - DRM_FIXED_ALMOST_ONE);
> -- 
> 2.42.1
> 


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