[PATCH] drm/i915/display: Remove FBC modulo 4 restriction for ADL+

[Govindapillai, Vinod]

On Wed, 2025-08-20 at 10:14 +0530, Uma Shankar wrote:
> FBC restriction where FBC is disabled for non-modulo 4 plane size
> (including plane size + yoffset) is fixed from ADL onwards in h/w.
> WA:22010751166
> 
> Relax the restriction for the same.
> 
> Credits-to: Vidya Srinivas <vidya.srinivas at intel.com>
> Signed-off-by: Uma Shankar <uma.shankar at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_fbc.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c b/drivers/gpu/drm/i915/display/intel_fbc.c
> index d4c5deff9cbe..bf257467a635 100644
> --- a/drivers/gpu/drm/i915/display/intel_fbc.c
> +++ b/drivers/gpu/drm/i915/display/intel_fbc.c
> @@ -1550,14 +1550,14 @@ static int intel_fbc_check_plane(struct intel_atomic_state *state,
>  	 * having a Y offset that isn't divisible by 4 causes FIFO underrun
>  	 * and screen flicker.
>  	 */
> -	if (DISPLAY_VER(display) >= 9 &&
> +	if (DISPLAY_VER(display) >= 9 && DISPLAY_VER(display) <= 12 &&

May be use IS_DISPLAY_VER(display, 9, 12) here and below as well?

Anyway,

Reviewed-by: Vinod Govindapillai <vinod.govindapillai at intel.com>


>  	    plane_state->view.color_plane[0].y & 3) {
>  		plane_state->no_fbc_reason = "plane start Y offset misaligned";
>  		return 0;
>  	}
>  
>  	/* Wa_22010751166: icl, ehl, tgl, dg1, rkl */
> -	if (DISPLAY_VER(display) >= 11 &&
> +	if ((DISPLAY_VER(display) == 11 || DISPLAY_VER(display) == 12) &&
>  	    (plane_state->view.color_plane[0].y +
>  	     (drm_rect_height(&plane_state->uapi.src) >> 16)) & 3) {
>  		plane_state->no_fbc_reason = "plane end Y offset misaligned";