Re: [PATCH RFC v4 3/7] drm/atomic: Move framebuffer checks to helper

[Dmitry Baryshkov <dmitry.baryshkov@linaro.org>]

On 30/06/2023 03:25, Jessica Zhang wrote:
> Currently framebuffer checks happen directly in
> drm_atomic_plane_check(). Move these checks into their own helper
> method.
> 
> Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
> ---
>   drivers/gpu/drm/drm_atomic.c | 130 ++++++++++++++++++++++++-------------------
>   1 file changed, 74 insertions(+), 56 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> index b4c6ffc438da..404b984d2d9f 100644
> --- a/drivers/gpu/drm/drm_atomic.c
> +++ b/drivers/gpu/drm/drm_atomic.c
> @@ -580,6 +580,76 @@ plane_switching_crtc(const struct drm_plane_state *old_plane_state,
>   	return true;
>   }
>   
> +static int drm_atomic_check_fb(const struct drm_plane_state *state)
> +{
> +	struct drm_plane *plane = state->plane;
> +	const struct drm_framebuffer *fb = state->fb;
> +	struct drm_mode_rect *clips;
> +
> +	uint32_t num_clips;
> +	unsigned int fb_width, fb_height;
> +	int ret;
> +
> +	/* Check whether this plane supports the fb pixel format. */
> +	ret = drm_plane_check_pixel_format(plane, fb->format->format,
> +					   fb->modifier);
> +
> +	if (ret) {
> +		drm_dbg_atomic(plane->dev,
> +			       "[PLANE:%d:%s] invalid pixel format %p4cc, modifier 0x%llx\n",
> +			       plane->base.id, plane->name,
> +			       &fb->format->format, fb->modifier);
> +		return ret;
> +	}
> +
> +	fb_width = fb->width << 16;
> +	fb_height = fb->height << 16;
> +
> +	/* Make sure source coordinates are inside the fb. */
> +	if (state->src_w > fb_width ||
> +	    state->src_x > fb_width - state->src_w ||
> +	    state->src_h > fb_height ||
> +	    state->src_y > fb_height - state->src_h) {
> +		drm_dbg_atomic(plane->dev,
> +			       "[PLANE:%d:%s] invalid source coordinates "
> +			       "%u.%06ux%u.%06u+%u.%06u+%u.%06u (fb %ux%u)\n",
> +			       plane->base.id, plane->name,
> +			       state->src_w >> 16,
> +			       ((state->src_w & 0xffff) * 15625) >> 10,
> +			       state->src_h >> 16,
> +			       ((state->src_h & 0xffff) * 15625) >> 10,
> +			       state->src_x >> 16,
> +			       ((state->src_x & 0xffff) * 15625) >> 10,
> +			       state->src_y >> 16,
> +			       ((state->src_y & 0xffff) * 15625) >> 10,
> +			       fb->width, fb->height);
> +		return -ENOSPC;
> +	}
> +
> +	clips = __drm_plane_get_damage_clips(state);
> +	num_clips = drm_plane_get_damage_clips_count(state);
> +
> +	/* Make sure damage clips are valid and inside the fb. */
> +	while (num_clips > 0) {
> +		if (clips->x1 >= clips->x2 ||
> +		    clips->y1 >= clips->y2 ||
> +		    clips->x1 < 0 ||
> +		    clips->y1 < 0 ||
> +		    clips->x2 > fb_width ||
> +		    clips->y2 > fb_height) {
> +			drm_dbg_atomic(plane->dev,
> +				       "[PLANE:%d:%s] invalid damage clip %d %d %d %d\n",
> +				       plane->base.id, plane->name, clips->x1,
> +				       clips->y1, clips->x2, clips->y2);
> +			return -EINVAL;
> +		}
> +		clips++;
> +		num_clips--;
> +	}
> +
> +	return 0;
> +}
> +
>   /**
>    * drm_atomic_plane_check - check plane state
>    * @old_plane_state: old plane state to check
> @@ -596,9 +666,6 @@ static int drm_atomic_plane_check(const struct drm_plane_state *old_plane_state,
>   	struct drm_plane *plane = new_plane_state->plane;
>   	struct drm_crtc *crtc = new_plane_state->crtc;
>   	const struct drm_framebuffer *fb = new_plane_state->fb;
> -	unsigned int fb_width, fb_height;
> -	struct drm_mode_rect *clips;
> -	uint32_t num_clips;
>   	int ret;
>   
>   	/* either *both* CRTC and FB must be set, or neither */
> @@ -625,17 +692,6 @@ static int drm_atomic_plane_check(const struct drm_plane_state *old_plane_state,
>   		return -EINVAL;
>   	}
>   
> -	/* Check whether this plane supports the fb pixel format. */
> -	ret = drm_plane_check_pixel_format(plane, fb->format->format,
> -					   fb->modifier);
> -	if (ret) {
> -		drm_dbg_atomic(plane->dev,
> -			       "[PLANE:%d:%s] invalid pixel format %p4cc, modifier 0x%llx\n",
> -			       plane->base.id, plane->name,
> -			       &fb->format->format, fb->modifier);
> -		return ret;
> -	}
> -
>   	/* Give drivers some help against integer overflows */
>   	if (new_plane_state->crtc_w > INT_MAX ||
>   	    new_plane_state->crtc_x > INT_MAX - (int32_t) new_plane_state->crtc_w ||
> @@ -649,49 +705,11 @@ static int drm_atomic_plane_check(const struct drm_plane_state *old_plane_state,
>   		return -ERANGE;
>   	}
>   
> -	fb_width = fb->width << 16;
> -	fb_height = fb->height << 16;
>   
> -	/* Make sure source coordinates are inside the fb. */
> -	if (new_plane_state->src_w > fb_width ||
> -	    new_plane_state->src_x > fb_width - new_plane_state->src_w ||
> -	    new_plane_state->src_h > fb_height ||
> -	    new_plane_state->src_y > fb_height - new_plane_state->src_h) {
> -		drm_dbg_atomic(plane->dev,
> -			       "[PLANE:%d:%s] invalid source coordinates "
> -			       "%u.%06ux%u.%06u+%u.%06u+%u.%06u (fb %ux%u)\n",
> -			       plane->base.id, plane->name,
> -			       new_plane_state->src_w >> 16,
> -			       ((new_plane_state->src_w & 0xffff) * 15625) >> 10,
> -			       new_plane_state->src_h >> 16,
> -			       ((new_plane_state->src_h & 0xffff) * 15625) >> 10,
> -			       new_plane_state->src_x >> 16,
> -			       ((new_plane_state->src_x & 0xffff) * 15625) >> 10,
> -			       new_plane_state->src_y >> 16,
> -			       ((new_plane_state->src_y & 0xffff) * 15625) >> 10,
> -			       fb->width, fb->height);
> -		return -ENOSPC;
> -	}
> -
> -	clips = __drm_plane_get_damage_clips(new_plane_state);
> -	num_clips = drm_plane_get_damage_clips_count(new_plane_state);
> -
> -	/* Make sure damage clips are valid and inside the fb. */
> -	while (num_clips > 0) {
> -		if (clips->x1 >= clips->x2 ||
> -		    clips->y1 >= clips->y2 ||
> -		    clips->x1 < 0 ||
> -		    clips->y1 < 0 ||
> -		    clips->x2 > fb_width ||
> -		    clips->y2 > fb_height) {
> -			drm_dbg_atomic(plane->dev,
> -				       "[PLANE:%d:%s] invalid damage clip %d %d %d %d\n",
> -				       plane->base.id, plane->name, clips->x1,
> -				       clips->y1, clips->x2, clips->y2);
> -			return -EINVAL;
> -		}
> -		clips++;
> -		num_clips--;
> +	if (fb) {

This doesn't only move code, but also changes semantics, making the 
checks optional if no FB is provided. Consider moving the condition to 
the next patch. Otherwise LGTM.

> +		ret = drm_atomic_check_fb(new_plane_state);
> +		if (ret)
> +			return ret;
>   	}
>   
>   	if (plane_switching_crtc(old_plane_state, new_plane_state)) {
> 

-- 
With best wishes
Dmitry