[Intel-gfx] [PATCH v4 2/2] drm/i915/lnl: FBC is supported with per pixel alpha

[Ville Syrjälä]

On Mon, Sep 04, 2023 at 02:55:17PM +0300, Vinod Govindapillai wrote:
> For LNL onwards, FBC can be supported on planes with per
> pixel alpha
> 
> Bspec: 69560
> Signed-off-by: Vinod Govindapillai <vinod.govindapillai at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_fbc.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c b/drivers/gpu/drm/i915/display/intel_fbc.c
> index a3999ad95a19..c0e4caec03ea 100644
> --- a/drivers/gpu/drm/i915/display/intel_fbc.c
> +++ b/drivers/gpu/drm/i915/display/intel_fbc.c
> @@ -1209,7 +1209,8 @@ static int intel_fbc_check_plane(struct intel_atomic_state *state,
>  		return 0;
>  	}
>  
> -	if (plane_state->hw.pixel_blend_mode != DRM_MODE_BLEND_PIXEL_NONE &&
> +	if (DISPLAY_VER(i915) < 20 &&

Bspec still says 15. Someone needs to figure this mess out for
all LNL patches.

> +	    plane_state->hw.pixel_blend_mode != DRM_MODE_BLEND_PIXEL_NONE &&
>  	    fb->format->has_alpha) {

We would have already rejected the pixel format earlier, so atm this
check is redundant.

>  		plane_state->no_fbc_reason = "per-pixel alpha not supported";
>  		return 0;
> -- 
> 2.34.1

-- 
Ville Syrjälä
Intel