drm/i915/pfit: Check pfit scaling factors on ILK-BDW

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@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241016143134.26903-3-ville.syrjala@linux.intel.com
Acked-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/display/intel_panel.c b/drivers/gpu/drm/i915/display/intel_panel.c
index b770171..fb7def7 100644 (file)
--- 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;
 }