Re: [PATCH 2/9] drm/i915: Clean up skl+ plane stride limits

[Jani Nikula <jani.nikula@linux.intel.com>]

On Mon, 06 May 2024, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> skl_plane_max_stride() is pretty messy. Streamline it and
> split it into clear skl+ vs. adl+ variants.
>
> TODO: Deal with icl and tgl strude limits properly
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>  .../drm/i915/display/skl_universal_plane.c    | 65 +++++++++++--------
>  1 file changed, 37 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/skl_universal_plane.c b/drivers/gpu/drm/i915/display/skl_universal_plane.c
> index 0a8e781a3648..b8103d6ebc1f 100644
> --- a/drivers/gpu/drm/i915/display/skl_universal_plane.c
> +++ b/drivers/gpu/drm/i915/display/skl_universal_plane.c
> @@ -461,41 +461,46 @@ static int icl_plane_max_height(const struct drm_framebuffer *fb,
>  }
>  
>  static unsigned int
> -skl_plane_max_stride(struct intel_plane *plane,
> -		     u32 pixel_format, u64 modifier,
> -		     unsigned int rotation)
> +plane_max_stride(struct intel_plane *plane,
> +		 u32 pixel_format, u64 modifier,
> +		 unsigned int rotation,
> +		 unsigned int max_pixels,
> +		 unsigned int max_bytes)
>  {
> -	struct drm_i915_private *i915 = to_i915(plane->base.dev);
>  	const struct drm_format_info *info = drm_format_info(pixel_format);
>  	int cpp = info->cpp[0];
> -	int max_horizontal_pixels = 8192;
> -	int max_stride_bytes;
> -
> -	if (DISPLAY_VER(i915) >= 13) {
> -		/*
> -		 * The stride in bytes must not exceed of the size
> -		 * of 128K bytes. For pixel formats of 64bpp will allow
> -		 * for a 16K pixel surface.
> -		 */
> -		max_stride_bytes = 131072;
> -		if (cpp == 8)
> -			max_horizontal_pixels = 16384;

The commit message doesn't mention anything about this being dropped.

BR,
Jani.

> -		else
> -			max_horizontal_pixels = 65536;
> -	} else {
> -		/*
> -		 * "The stride in bytes must not exceed the
> -		 * of the size of 8K pixels and 32K bytes."
> -		 */
> -		max_stride_bytes = 32768;
> -	}
>  
>  	if (drm_rotation_90_or_270(rotation))
> -		return min(max_horizontal_pixels, max_stride_bytes / cpp);
> +		return min(max_pixels, max_bytes / cpp);
>  	else
> -		return min(max_horizontal_pixels * cpp, max_stride_bytes);
> +		return min(max_pixels * cpp, max_bytes);
>  }
>  
> +static unsigned int
> +adl_plane_max_stride(struct intel_plane *plane,
> +		     u32 pixel_format, u64 modifier,
> +		     unsigned int rotation)
> +{
> +	unsigned int max_pixels = 65536; /* PLANE_OFFSET limit */
> +	unsigned int max_bytes = 128 * 1024;
> +
> +	return plane_max_stride(plane, pixel_format,
> +				modifier, rotation,
> +				max_pixels, max_bytes);
> +}
> +
> +static unsigned int
> +skl_plane_max_stride(struct intel_plane *plane,
> +		     u32 pixel_format, u64 modifier,
> +		     unsigned int rotation)
> +{
> +	unsigned int max_pixels = 8192; /* PLANE_OFFSET limit */
> +	unsigned int max_bytes = 32 * 1024;
> +
> +	return plane_max_stride(plane, pixel_format,
> +				modifier, rotation,
> +				max_pixels, max_bytes);
> +}
>  
>  /* Preoffset values for YUV to RGB Conversion */
>  #define PREOFF_YUV_TO_RGB_HI		0x1800
> @@ -2357,7 +2362,11 @@ skl_universal_plane_create(struct drm_i915_private *dev_priv,
>  		plane->min_cdclk = skl_plane_min_cdclk;
>  	}
>  
> -	plane->max_stride = skl_plane_max_stride;
> +	if (DISPLAY_VER(dev_priv) >= 13)
> +		plane->max_stride = adl_plane_max_stride;
> +	else
> +		plane->max_stride = skl_plane_max_stride;
> +
>  	if (DISPLAY_VER(dev_priv) >= 11) {
>  		plane->update_noarm = icl_plane_update_noarm;
>  		plane->update_arm = icl_plane_update_arm;

-- 
Jani Nikula, Intel