[Intel-gfx] [PATCH] drm/i915/gen9: Give one extra block per line for SKL plane WM calculations

[Lyude]

Reviewed-by: Lyude <cpaul at redhat.com>

On Thu, 2016-08-04 at 14:08 -0700, Matt Roper wrote:
> The bspec was updated a couple weeks ago to add an extra block per
> line
> to plane watermark calculations for linear pixel formats.
> 
> Bspec update 115327 description:
>   "Gen9+ - Updated the plane blocks per line calculation for linear
>   cases. Adds +1 for all linear cases to handle the non-block aligned
>   stride cases."
> 
> Cc: Lyude <cpaul at redhat.com>
> Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c
> b/drivers/gpu/drm/i915/intel_pm.c
> index 4317cdf..6bd352a 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -3352,6 +3352,8 @@ static uint32_t skl_wm_method2(uint32_t
> pixel_rate, uint32_t pipe_htotal,
>  		plane_bytes_per_line *= 4;
>  		plane_blocks_per_line =
> DIV_ROUND_UP(plane_bytes_per_line, 512);
>  		plane_blocks_per_line /= 4;
> +	} else if (tiling == DRM_FORMAT_MOD_NONE) {
> +		plane_blocks_per_line =
> DIV_ROUND_UP(plane_bytes_per_line, 512) + 1;
>  	} else {
>  		plane_blocks_per_line =
> DIV_ROUND_UP(plane_bytes_per_line, 512);
>  	}
-- 
Cheers,
	Lyude