Re: [PATCH] drm/i915/fbc: Apply wa_15018326506

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

On Fri, 07 Nov 2025, Vinod Govindapillai <vinod.govindapillai@intel.com> wrote:
> Disable FBC as part for the wa for the bmg variant
>
> Bspec: 74212
> Signed-off-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display_wa.c |  4 ++++
>  drivers/gpu/drm/i915/display/intel_display_wa.h |  1 +
>  drivers/gpu/drm/i915/display/intel_fbc.c        | 10 ++++++++++
>  3 files changed, 15 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_wa.c b/drivers/gpu/drm/i915/display/intel_display_wa.c
> index c528aaa679ca..ba2272d85a04 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_wa.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_wa.c
> @@ -10,6 +10,7 @@
>  #include "intel_display_core.h"
>  #include "intel_display_regs.h"
>  #include "intel_display_wa.h"
> +#include "intel_step.h"
>  
>  static void gen11_display_wa_apply(struct intel_display *display)
>  {
> @@ -69,6 +70,9 @@ bool __intel_display_wa(struct intel_display *display, enum intel_display_wa wa,
>  		return DISPLAY_VER(display) == 13;
>  	case INTEL_DISPLAY_WA_22014263786:
>  		return IS_DISPLAY_VERx100(display, 1100, 1400);
> +	case INTEL_DISPLAY_WA_15018326506:
> +		return DISPLAY_VERx100(display) == 1401 &&
> +		       INTEL_DISPLAY_STEP(display) == STEP_C0;

IS_DISPLAY_VERx100_STEP().

>  	default:
>  		drm_WARN(display->drm, 1, "Missing Wa number: %s\n", name);
>  		break;
> diff --git a/drivers/gpu/drm/i915/display/intel_display_wa.h b/drivers/gpu/drm/i915/display/intel_display_wa.h
> index 3644e8e2b724..f648b00cb97d 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_wa.h
> +++ b/drivers/gpu/drm/i915/display/intel_display_wa.h
> @@ -26,6 +26,7 @@ enum intel_display_wa {
>  	INTEL_DISPLAY_WA_16025573575,
>  	INTEL_DISPLAY_WA_14011503117,
>  	INTEL_DISPLAY_WA_22014263786,
> +	INTEL_DISPLAY_WA_15018326506,
>  };
>  
>  bool __intel_display_wa(struct intel_display *display, enum intel_display_wa wa, const char *name);
> diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c b/drivers/gpu/drm/i915/display/intel_fbc.c
> index a1e3083022ee..16cd99db2978 100644
> --- a/drivers/gpu/drm/i915/display/intel_fbc.c
> +++ b/drivers/gpu/drm/i915/display/intel_fbc.c
> @@ -1521,6 +1521,16 @@ static int intel_fbc_check_plane(struct intel_atomic_state *state,
>  		return 0;
>  	}
>  
> +	/*
> +	 * wa_15018326506:
> +	 * Fixes: Underrun during media decode
> +	 * Workaround: Do not enable FBC
> +	 */
> +	if (intel_display_wa(display, 15018326506)) {
> +		plane_state->no_fbc_reason = "Wa_15018326506";
> +		return 0;
> +	}
> +
>  	/* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl,bxt */
>  	if (intel_display_vtd_active(display) &&
>  	    (display->platform.skylake || display->platform.broxton)) {

-- 
Jani Nikula, Intel