Re: [PATCH 1/5] drm: Define DRM_FORMAT_MAX_PLANES

[Maxime Ripard <maxime@cerno.tech>]

Hi,

On Thu, Jul 15, 2021 at 08:01:29PM +0200, Thomas Zimmermann wrote:
> DRM uses a magic number of 4 for the maximum number of planes per color
> format. Declare this constant via DRM_FORMAT_MAX_PLANES and update the
> related code.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>  drivers/gpu/drm/drm_gem_framebuffer_helper.c | 14 ++++++++------
>  include/drm/drm_fourcc.h                     | 13 +++++++++----
>  include/drm/drm_framebuffer.h                |  8 ++++----
>  include/drm/drm_gem_atomic_helper.h          |  2 +-
>  4 files changed, 22 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
> index e2c68822e05c..975a3df0561e 100644
> --- a/drivers/gpu/drm/drm_gem_framebuffer_helper.c
> +++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
> @@ -48,7 +48,7 @@
>  struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb,
>  					  unsigned int plane)
>  {
> -	if (plane >= 4)
> +	if (plane >= ARRAY_SIZE(fb->obj))
>  		return NULL;

This doesn't look related to what's mentionned in the commit log though?

>  	return fb->obj[plane];
> @@ -62,7 +62,8 @@ drm_gem_fb_init(struct drm_device *dev,
>  		 struct drm_gem_object **obj, unsigned int num_planes,
>  		 const struct drm_framebuffer_funcs *funcs)
>  {
> -	int ret, i;
> +	unsigned int i;
> +	int ret;
>  
>  	drm_helper_mode_fill_fb_struct(dev, fb, mode_cmd);
>  
> @@ -86,9 +87,9 @@ drm_gem_fb_init(struct drm_device *dev,
>   */
>  void drm_gem_fb_destroy(struct drm_framebuffer *fb)
>  {
> -	int i;
> +	size_t i;
>  
> -	for (i = 0; i < 4; i++)
> +	for (i = 0; i < ARRAY_SIZE(fb->obj); i++)
>  		drm_gem_object_put(fb->obj[i]);

Ditto

Both these changes look fine though, but I guess you should just mention it

Maxime