Re: [PATCH 6/9] drm/i915/pfit: Check pfit destination window on ILK-BDW

[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>
>
> The ILK-BDW panel fitter has several restrictions on the
> destination window size. Check for those and reject the
> configuration if things aren't entirely proper.
>
> 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 | 55 ++++++++++++++++++++++
>  1 file changed, 55 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
> index 593e41907d53..d66ce8537f7d 100644
> --- a/drivers/gpu/drm/i915/display/intel_panel.c
> +++ b/drivers/gpu/drm/i915/display/intel_panel.c
> @@ -383,6 +383,57 @@ void intel_panel_add_encoder_fixed_mode(struct intel_connector *connector,
>  				   "current (BIOS)");
>  }
>  
> +static int intel_pch_pfit_check_dst_window(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;
> +	const struct drm_rect *dst = &crtc_state->pch_pfit.dst;
> +	int width = drm_rect_width(dst);
> +	int height = drm_rect_height(dst);
> +	int x = dst->x1;
> +	int y = dst->y1;
> +
> +	if (adjusted_mode->flags & DRM_MODE_FLAG_INTERLACE &&
> +	    (y & 1 || height & 1)) {
> +		drm_dbg_kms(display->drm,
> +			    "[CRTC:%d:%s] pfit window (" DRM_RECT_FMT ") misaligned for interlaced output\n",
> +			    crtc->base.base.id, crtc->base.name, DRM_RECT_ARG(dst));
> +		return -EINVAL;
> +	}
> +
> +	/*
> +	 * "Restriction : When pipe scaling is enabled, the scaled
> +	 *  output must equal the pipe active area, so Pipe active
> +	 *  size = (2 * PF window position) + PF window size."
> +	 *
> +	 * The vertical direction seems more forgiving than the
> +	 * horizontal direction, but still has some issues so
> +	 * let's follow the same hard rule for both.
> +	 */
> +	if (adjusted_mode->crtc_hdisplay != 2 * x + width ||
> +	    adjusted_mode->crtc_vdisplay != 2 * y + height) {
> +		drm_dbg_kms(display->drm,
> +			    "[CRTC:%d:%s] pfit window (" DRM_RECT_FMT ") not centered\n",
> +			    crtc->base.base.id, crtc->base.name, DRM_RECT_ARG(dst));
> +		return -EINVAL;
> +	}
> +
> +	/*
> +	 * "Restriction : The X position must not be programmed
> +	 *  to be 1 (28:16=0 0000 0000 0001b)."
> +	 */
> +	if (x == 1) {
> +		drm_dbg_kms(display->drm,
> +			    "[CRTC:%d:%s] pfit window (" DRM_RECT_FMT ") badly positioned\n",
> +			    crtc->base.base.id, crtc->base.name, DRM_RECT_ARG(dst));
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
>  static int intel_pch_pfit_check_src_size(const struct intel_crtc_state *crtc_state)
>  {
>  	struct intel_display *display = to_intel_display(crtc_state);
> @@ -575,6 +626,10 @@ static int pch_panel_fitting(struct intel_crtc_state *crtc_state,
>  	if (DISPLAY_VER(display) >= 9)
>  		return 0;
>  
> +	ret = intel_pch_pfit_check_dst_window(crtc_state);
> +	if (ret)
> +		return ret;
> +
>  	ret = intel_pch_pfit_check_src_size(crtc_state);
>  	if (ret)
>  		return ret;

-- 
Jani Nikula, Intel