[Intel-gfx] [PATCH 14/23] drm/i915/intel_fb: Factor out convert_plane_offset_to_xy()

[Ville Syrjälä]

On Thu, Mar 11, 2021 at 12:17:27AM +0200, Imre Deak wrote:
> Factor out to a new function the logic to convert the FB plane offset to
> x/y and check the validity of x/y, with the goal to make
> intel_fill_fb_info() more readable.
> 
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_fb.c | 70 +++++++++++++++----------
>  1 file changed, 42 insertions(+), 28 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_fb.c b/drivers/gpu/drm/i915/display/intel_fb.c
> index b96849ec32df..806341c229f0 100644
> --- a/drivers/gpu/drm/i915/display/intel_fb.c
> +++ b/drivers/gpu/drm/i915/display/intel_fb.c
> @@ -400,10 +400,10 @@ static int intel_fb_offset_to_xy(int *x, int *y,
>  	return 0;
>  }
>  
> -static int intel_fb_check_ccs_xy(struct drm_framebuffer *fb, int ccs_plane, int x, int y)
> +static int intel_fb_check_ccs_xy(const struct drm_framebuffer *fb, int ccs_plane, int x, int y)
>  {
>  	struct drm_i915_private *i915 = to_i915(fb->dev);
> -	struct intel_framebuffer *intel_fb = to_intel_framebuffer(fb);
> +	const struct intel_framebuffer *intel_fb = to_intel_framebuffer(fb);
>  	int main_plane;
>  	int hsub, vsub;
>  	int tile_width, tile_height;
> @@ -520,6 +520,45 @@ static bool intel_plane_needs_remap(const struct intel_plane_state *plane_state)
>  	return stride > max_stride;
>  }
>  
> +static int convert_plane_offset_to_xy(const struct intel_framebuffer *fb, int color_plane,
> +				      int plane_width, int *x, int *y)
> +{
> +	const struct drm_framebuffer *drm_fb = &fb->base;

Not a fan of these aliasing pointers. I know that the fb 
stuff is a bit of a mess when it comes to the drm_ vs. intel_
usage.

We've mostly cleaned up that stuff for plane/crtc/etc. by just
avoiding the aliasing pointers and just using foo->base where
appropriate. Not sure how that sort of approach would look in
the end of fbs?

> +	struct drm_i915_gem_object *obj = intel_fb_obj(drm_fb);
> +	int ret;
> +
> +	ret = intel_fb_offset_to_xy(x, y, drm_fb, color_plane);
> +	if (ret) {
> +		drm_dbg_kms(drm_fb->dev,
> +			    "bad fb plane %d offset: 0x%x\n",
> +			    color_plane, drm_fb->offsets[color_plane]);
> +		return ret;
> +	}
> +
> +	ret = intel_fb_check_ccs_xy(drm_fb, color_plane, *x, *y);
> +	if (ret)
> +		return ret;
> +
> +	/*
> +	 * The fence (if used) is aligned to the start of the object
> +	 * so having the framebuffer wrap around across the edge of the
> +	 * fenced region doesn't really work. We have no API to configure
> +	 * the fence start offset within the object (nor could we probably
> +	 * on gen2/3). So it's just easier if we just require that the
> +	 * fb layout agrees with the fence layout. We already check that the
> +	 * fb stride matches the fence stride elsewhere.
> +	 */
> +	if (color_plane == 0 && i915_gem_object_is_tiled(obj) &&
> +	    (*x + plane_width) * drm_fb->format->cpp[color_plane] > drm_fb->pitches[color_plane]) {
> +		drm_dbg_kms(drm_fb->dev,
> +			    "bad fb plane %d offset: 0x%x\n",
> +			    color_plane, drm_fb->offsets[color_plane]);
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
>  /*
>   * Setup the rotated view for an FB plane and return the size the GTT mapping
>   * requires for this view.
> @@ -611,35 +650,10 @@ int intel_fill_fb_info(struct drm_i915_private *i915, struct drm_framebuffer *fb
>  		cpp = fb->format->cpp[i];
>  		intel_fb_plane_dims(&width, &height, fb, i);
>  
> -		ret = intel_fb_offset_to_xy(&x, &y, fb, i);
> -		if (ret) {
> -			drm_dbg_kms(&i915->drm,
> -				    "bad fb plane %d offset: 0x%x\n",
> -				    i, fb->offsets[i]);
> -			return ret;
> -		}
> -
> -		ret = intel_fb_check_ccs_xy(fb, i, x, y);
> +		ret = convert_plane_offset_to_xy(intel_fb, i, width, &x, &y);
>  		if (ret)
>  			return ret;
>  
> -		/*
> -		 * The fence (if used) is aligned to the start of the object
> -		 * so having the framebuffer wrap around across the edge of the
> -		 * fenced region doesn't really work. We have no API to configure
> -		 * the fence start offset within the object (nor could we probably
> -		 * on gen2/3). So it's just easier if we just require that the
> -		 * fb layout agrees with the fence layout. We already check that the
> -		 * fb stride matches the fence stride elsewhere.
> -		 */
> -		if (i == 0 && i915_gem_object_is_tiled(obj) &&
> -		    (x + width) * cpp > fb->pitches[i]) {
> -			drm_dbg_kms(&i915->drm,
> -				    "bad fb plane %d offset: 0x%x\n",
> -				     i, fb->offsets[i]);
> -			return -EINVAL;
> -		}
> -
>  		/*
>  		 * First pixel of the framebuffer from
>  		 * the start of the normal gtt mapping.
> -- 
> 2.25.1
> 
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-- 
Ville Syrjälä
Intel