[PATCH v6 4/9] drm: Extend framebuffer_check to handle formats with cpp/char_per_block 0

[Daniel Vetter]

On Mon, Oct 29, 2018 at 05:14:39PM +0000, Alexandru-Cosmin Gheorghe wrote:
> For formats that are supported only with non-linear modifiers it
> doesn't make to much sense to define cpp or char_per_block, so that
> will be set to 0.
> 
> This patch adds a restriction to force having a modifier attached when
> cpp/char_per_block is 0, and to bypass checking the pitch restriction.
> 
> This had been discussed here.
> [1] https://people.freedesktop.org/~cbrill/dri-log/?channel=dri-devel&highlight_names=&date=2018-09-13&show_html=true
> 
> Reviewed-by: Brian Starkey <brian.starkey at arm.com>
> Signed-off-by: Alexandru Gheorghe <alexandru-cosmin.gheorghe at arm.com>

(kerneldoc is already part of an earlier patch)

Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> ---
>  drivers/gpu/drm/drm_framebuffer.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
> index 6aca8a1ccdb6..167c1c4544af 100644
> --- a/drivers/gpu/drm/drm_framebuffer.c
> +++ b/drivers/gpu/drm/drm_framebuffer.c
> @@ -195,8 +195,14 @@ static int framebuffer_check(struct drm_device *dev,
>  	for (i = 0; i < info->num_planes; i++) {
>  		unsigned int width = fb_plane_width(r->width, info, i);
>  		unsigned int height = fb_plane_height(r->height, info, i);
> +		unsigned int block_size = info->char_per_block[i];
>  		u64 min_pitch = drm_format_info_min_pitch(info, i, width);
>  
> +		if (!block_size && (r->modifier[i] == DRM_FORMAT_MOD_LINEAR)) {
> +			DRM_DEBUG_KMS("Format requires non-linear modifier for plane %d\n", i);
> +			return -EINVAL;
> +		}
> +
>  		if (!r->handles[i]) {
>  			DRM_DEBUG_KMS("no buffer object handle for plane %d\n", i);
>  			return -EINVAL;
> @@ -208,7 +214,7 @@ static int framebuffer_check(struct drm_device *dev,
>  		if ((uint64_t) height * r->pitches[i] + r->offsets[i] > UINT_MAX)
>  			return -ERANGE;
>  
> -		if (r->pitches[i] < min_pitch) {
> +		if (block_size && r->pitches[i] < min_pitch) {
>  			DRM_DEBUG_KMS("bad pitch %u for plane %d\n", r->pitches[i], i);
>  			return -EINVAL;
>  		}
> -- 
> 2.19.1
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch