[Intel-gfx] [PATCH] drm/i915/display/adlp: Disable underrun recovery

[Ville Syrjälä]

On Wed, Nov 03, 2021 at 06:08:58PM -0700, José Roberto de Souza wrote:
> It was also defeatured for ADL-P and other platforms.
> 
> BSpec: 55424
> Signed-off-by: José Roberto de Souza <jose.souza at intel.com>

Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Can you also nuke the now pointless bubble counter programming
as well?

> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 39 ++++----------------
>  1 file changed, 7 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 29392dfc46c8d..64406408ba590 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -956,26 +956,6 @@ void intel_display_finish_reset(struct drm_i915_private *dev_priv)
>  	clear_bit_unlock(I915_RESET_MODESET, &dev_priv->gt.reset.flags);
>  }
>  
> -static bool underrun_recovery_supported(const struct intel_crtc_state *crtc_state)
> -{
> -	if (crtc_state->pch_pfit.enabled &&
> -	    (crtc_state->pipe_src_w > drm_rect_width(&crtc_state->pch_pfit.dst) ||
> -	     crtc_state->pipe_src_h > drm_rect_height(&crtc_state->pch_pfit.dst) ||
> -	     crtc_state->output_format == INTEL_OUTPUT_FORMAT_YCBCR420))
> -		return false;
> -
> -	if (crtc_state->dsc.compression_enable)
> -		return false;
> -
> -	if (crtc_state->has_psr2)
> -		return false;
> -
> -	if (crtc_state->splitter.enable)
> -		return false;
> -
> -	return true;
> -}
> -
>  static void icl_set_pipe_chicken(const struct intel_crtc_state *crtc_state)
>  {
>  	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> @@ -999,19 +979,14 @@ static void icl_set_pipe_chicken(const struct intel_crtc_state *crtc_state)
>  	 */
>  	tmp |= PIXEL_ROUNDING_TRUNC_FB_PASSTHRU;
>  
> -	if (IS_DG2(dev_priv)) {
> -		/*
> -		 * Underrun recovery must always be disabled on DG2.  However
> -		 * the chicken bit meaning is inverted compared to other
> -		 * platforms.
> -		 */
> +	/*
> +	 * Underrun recovery must always be disabled on display 13+.
> +	 * DG2 chicken bit meaning is inverted compared to other platforms.
> +	 */
> +	if (IS_DG2(dev_priv))
>  		tmp &= ~UNDERRUN_RECOVERY_ENABLE_DG2;
> -	} else if (DISPLAY_VER(dev_priv) >= 13) {
> -		if (underrun_recovery_supported(crtc_state))
> -			tmp &= ~UNDERRUN_RECOVERY_DISABLE_ADLP;
> -		else
> -			tmp |= UNDERRUN_RECOVERY_DISABLE_ADLP;
> -	}
> +	else if (DISPLAY_VER(dev_priv) >= 13)
> +		tmp |= UNDERRUN_RECOVERY_DISABLE_ADLP;
>  
>  	intel_de_write(dev_priv, PIPE_CHICKEN(pipe), tmp);
>  }
> -- 
> 2.33.1

-- 
Ville Syrjälä
Intel