[PATCH 1/3] drm: Tune up error message during format->bpp/cpp conversion

[Ville Syrjälä]

On Thu, May 12, 2016 at 04:00:38PM +0300, Imre Deak wrote:
> Returning a 0 bpp/cpp value from these functions isn't ever valid. In
> many cases it can also lead to a div-by-zero possibly at some later
> point in time, so make sure we catch such errors as soon as possible via
> louder error reporting.
> 
> CC: Dave Airlie <airlied at redhat.com>
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/gpu/drm/drm_crtc.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
> index 70f9c68..3a32606 100644
> --- a/drivers/gpu/drm/drm_crtc.c
> +++ b/drivers/gpu/drm/drm_crtc.c
> @@ -5610,8 +5610,8 @@ void drm_fb_get_bpp_depth(uint32_t format, unsigned int *depth,
>  		*bpp = 32;
>  		break;
>  	default:
> -		DRM_DEBUG_KMS("unsupported pixel format %s\n",
> -			      drm_get_format_name(format));
> +		WARN(1, "unsupported pixel format %s\n",
> +		     drm_get_format_name(format));

NAK. This will happen every time drm_helper_mode_fill_fb_struct()
is called with a non-RGB format.

>  		*depth = 0;
>  		*bpp = 0;
>  		break;
> @@ -5666,8 +5666,12 @@ int drm_format_plane_cpp(uint32_t format, int plane)
>  	unsigned int depth;
>  	int bpp;
>  
> -	if (plane >= drm_format_num_planes(format))
> +	if (plane >= drm_format_num_planes(format)) {
> +		WARN(1, "invalid plane %d for format %s\n",
> +		     plane, drm_get_format_name(format));
> +

We have this check in many places. Should either convert all or none.

>  		return 0;
> +	}
>  
>  	switch (format) {
>  	case DRM_FORMAT_YUYV:
> -- 
> 2.5.0
> 
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-- 
Ville Syrjälä
Intel OTC