Re: [PATCH 4/9] drm/i915/pfit: Check pfit minimum timings in pre-SKL

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

On Wed, 16 Oct 2024, Ville Syrjala <ville.syrjala@linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> Transcoder hdisplay/vdisplay have documented minimum limits
> when using the panel fitter. Enforce those limits for all
> pre-SKL platforms. SKL+ handles everything in the unified
> scaler code instead.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Acked-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_panel.c | 59 +++++++++++++++++++++-
>  1 file changed, 58 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
> index 89cac3b3fd02..dc843892b01b 100644
> --- a/drivers/gpu/drm/i915/display/intel_panel.c
> +++ b/drivers/gpu/drm/i915/display/intel_panel.c
> @@ -456,6 +456,24 @@ static int intel_pch_pfit_check_scaling(const struct intel_crtc_state *crtc_stat
>  	return 0;
>  }
>  
> +static int intel_pch_pfit_check_timings(const struct intel_crtc_state *crtc_state)
> +{
> +	struct intel_display *display = to_intel_display(crtc_state);
> +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> +	const struct drm_display_mode *adjusted_mode =
> +		&crtc_state->hw.adjusted_mode;
> +
> +	if (adjusted_mode->crtc_vdisplay < 7) {
> +		drm_dbg_kms(display->drm,
> +			    "[CRTC:%d:%s] vertical active (%d) below minimum (%d) for pfit\n",
> +			    crtc->base.base.id, crtc->base.name,
> +			    adjusted_mode->crtc_vdisplay, 7);
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
>  /* adjusted_mode has been preset to be the panel's fixed mode */
>  static int pch_panel_fitting(struct intel_crtc_state *crtc_state,
>  			     const struct drm_connector_state *conn_state)
> @@ -542,6 +560,10 @@ static int pch_panel_fitting(struct intel_crtc_state *crtc_state,
>  	if (ret)
>  		return ret;
>  
> +	ret = intel_pch_pfit_check_timings(crtc_state);
> +	if (ret)
> +		return ret;
> +
>  	return 0;
>  }
>  
> @@ -678,6 +700,38 @@ static void i9xx_scale_aspect(struct intel_crtc_state *crtc_state,
>  	}
>  }
>  
> +static int intel_gmch_pfit_check_timings(const struct intel_crtc_state *crtc_state)
> +{
> +	struct intel_display *display = to_intel_display(crtc_state);
> +	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> +	const struct drm_display_mode *adjusted_mode =
> +		&crtc_state->hw.adjusted_mode;
> +	int min;
> +
> +	if (DISPLAY_VER(display) >= 4)
> +		min = 3;
> +	else
> +		min = 2;
> +
> +	if (adjusted_mode->crtc_hdisplay < min) {
> +		drm_dbg_kms(display->drm,
> +			    "[CRTC:%d:%s] horizontal active (%d) below minimum (%d) for pfit\n",
> +			    crtc->base.base.id, crtc->base.name,
> +			    adjusted_mode->crtc_hdisplay, min);
> +		return -EINVAL;
> +	}
> +
> +	if (adjusted_mode->crtc_vdisplay < min) {
> +		drm_dbg_kms(display->drm,
> +			    "[CRTC:%d:%s] vertical active (%d) below minimum (%d) for pfit\n",
> +			    crtc->base.base.id, crtc->base.name,
> +			    adjusted_mode->crtc_vdisplay, min);
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
>  static int gmch_panel_fitting(struct intel_crtc_state *crtc_state,
>  			      const struct drm_connector_state *conn_state)
>  {
> @@ -772,7 +826,10 @@ static int gmch_panel_fitting(struct intel_crtc_state *crtc_state,
>  	crtc_state->gmch_pfit.pgm_ratios = pfit_pgm_ratios;
>  	crtc_state->gmch_pfit.lvds_border_bits = border;
>  
> -	return 0;
> +	if ((pfit_control & PFIT_ENABLE) == 0)
> +		return 0;
> +
> +	return intel_gmch_pfit_check_timings(crtc_state);
>  }
>  
>  int intel_panel_fitting(struct intel_crtc_state *crtc_state,

-- 
Jani Nikula, Intel