[PATCH 2/9] drm/i915/pfit: Check pfit scaling factors on ILK-BDW

[Jani Nikula]

On Wed, 16 Oct 2024, Ville Syrjala <ville.syrjala at linux.intel.com> wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> Make sure we're not exceeding the max scaling factors for the panel
> fitter on ILK-BDW. SKL+ is skipped here since this is all supposed to
> be handled by the unified scaler code.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

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

> ---
>  drivers/gpu/drm/i915/display/intel_panel.c | 39 ++++++++++++++++++++++
>  1 file changed, 39 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
> index b77017144818..fb7def772376 100644
> --- a/drivers/gpu/drm/i915/display/intel_panel.c
> +++ b/drivers/gpu/drm/i915/display/intel_panel.c
> @@ -421,6 +421,41 @@ static int intel_pch_pfit_check_src_size(const struct intel_crtc_state *crtc_sta
>  	return 0;
>  }
>  
> +static int intel_pch_pfit_check_scaling(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_rect *dst = &crtc_state->pch_pfit.dst;
> +	int pipe_src_w = drm_rect_width(&crtc_state->pipe_src);
> +	int pipe_src_h = drm_rect_height(&crtc_state->pipe_src);
> +	int hscale, vscale, max_scale = 0x12000; /* 1.125 */
> +	struct drm_rect src;
> +
> +	drm_rect_init(&src, 0, 0, pipe_src_w << 16, pipe_src_h << 16);
> +
> +	hscale = drm_rect_calc_hscale(&src, dst, 0, max_scale);
> +	if (hscale < 0) {
> +		drm_dbg_kms(display->drm,
> +			    "[CRTC:%d:%s] pfit horizontal downscaling (%d->%d) exceeds max (0x%x)\n",
> +			    crtc->base.base.id, crtc->base.name,
> +			    pipe_src_w, drm_rect_width(dst),
> +			    max_scale);
> +		return hscale;
> +	}
> +
> +	vscale = drm_rect_calc_vscale(&src, dst, 0, max_scale);
> +	if (vscale < 0) {
> +		drm_dbg_kms(display->drm,
> +			    "[CRTC:%d:%s] pfit vertical downscaling (%d->%d) exceeds max (0x%x)\n",
> +			    crtc->base.base.id, crtc->base.name,
> +			    pipe_src_h, drm_rect_height(dst),
> +			    max_scale);
> +		return vscale;
> +	}
> +
> +	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)
> @@ -503,6 +538,10 @@ static int pch_panel_fitting(struct intel_crtc_state *crtc_state,
>  	if (ret)
>  		return ret;
>  
> +	ret = intel_pch_pfit_check_scaling(crtc_state);
> +	if (ret)
> +		return ret;
> +
>  	return 0;
>  }

-- 
Jani Nikula, Intel