drm/edid: Split deep color modes between RGB and YUV444

The current code assumes that the RGB444 and YUV444 formats are the
same, but the HDMI 2.0 specification states that:

   The three DC_XXbit bits above only indicate support for RGB 4:4:4 at
   that pixel size. Support for YCBCR 4:4:4 in Deep Color modes is
   indicated with the DC_Y444 bit. If DC_Y444 is set, then YCBCR 4:4:4
   is supported for all modes indicated by the DC_XXbit flags.

So if we have YUV444 support and any DC_XXbit flag set but the DC_Y444
flag isn't, we'll assume that we support that deep colour mode for
YUV444 which breaks the specification.

In order to fix this, let's split the edid_hdmi_dc_modes field in struct
drm_display_info into two fields, one for RGB444 and one for YUV444.
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Fixes: d0c94692 ("drm/edid: Parse and handle HDMI deep color modes.")
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220120151625.594595-4-maxime@cerno.tech

drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c

@@ -175,7 +175,7 @@ int amdgpu_connector_get_monitor_bpc(struct drm_connector *connector)
 
 			/* Check if bpc is within clock limit. Try to degrade gracefully otherwise */
 			if ((bpc == 12) && (mode_clock * 3/2 > max_tmds_clock)) {
-				if ((connector->display_info.edid_hdmi_dc_modes & DRM_EDID_HDMI_DC_30) &&
+				if ((connector->display_info.edid_hdmi_rgb444_dc_modes & DRM_EDID_HDMI_DC_30) &&
 				    (mode_clock * 5/4 <= max_tmds_clock))
 					bpc = 10;
 				else

drivers/gpu/drm/drm_edid.c

@@ -5086,21 +5086,21 @@ static void drm_parse_hdmi_deep_color_info(struct drm_connector *connector,
 
 	if (hdmi[6] & DRM_EDID_HDMI_DC_30) {
 		dc_bpc = 10;
-		info->edid_hdmi_dc_modes |= DRM_EDID_HDMI_DC_30;
+		info->edid_hdmi_rgb444_dc_modes |= DRM_EDID_HDMI_DC_30;
 		DRM_DEBUG("%s: HDMI sink does deep color 30.\n",
 			  connector->name);
 	}
 
 	if (hdmi[6] & DRM_EDID_HDMI_DC_36) {
 		dc_bpc = 12;
-		info->edid_hdmi_dc_modes |= DRM_EDID_HDMI_DC_36;
+		info->edid_hdmi_rgb444_dc_modes |= DRM_EDID_HDMI_DC_36;
 		DRM_DEBUG("%s: HDMI sink does deep color 36.\n",
 			  connector->name);
 	}
 
 	if (hdmi[6] & DRM_EDID_HDMI_DC_48) {
 		dc_bpc = 16;
-		info->edid_hdmi_dc_modes |= DRM_EDID_HDMI_DC_48;
+		info->edid_hdmi_rgb444_dc_modes |= DRM_EDID_HDMI_DC_48;
 		DRM_DEBUG("%s: HDMI sink does deep color 48.\n",
 			  connector->name);
 	}
@@ -5117,6 +5117,7 @@ static void drm_parse_hdmi_deep_color_info(struct drm_connector *connector,
 
 	/* YCRCB444 is optional according to spec. */
 	if (hdmi[6] & DRM_EDID_HDMI_DC_Y444) {
+		info->edid_hdmi_ycbcr444_dc_modes = info->edid_hdmi_rgb444_dc_modes;
 		DRM_DEBUG("%s: HDMI sink does YCRCB444 in deep color.\n",
 			  connector->name);
 	}

drivers/gpu/drm/i915/display/intel_hdmi.c

@@ -1912,7 +1912,7 @@ static bool intel_hdmi_sink_bpc_possible(struct drm_connector *connector,
 		if (ycbcr420_output)
 			return hdmi->y420_dc_modes & DRM_EDID_YCBCR420_DC_36;
 		else
-			return info->edid_hdmi_dc_modes & DRM_EDID_HDMI_DC_36;
+			return info->edid_hdmi_rgb444_dc_modes & DRM_EDID_HDMI_DC_36;
 	case 10:
 		if (!has_hdmi_sink)
 			return false;
@@ -1920,7 +1920,7 @@ static bool intel_hdmi_sink_bpc_possible(struct drm_connector *connector,
 		if (ycbcr420_output)
 			return hdmi->y420_dc_modes & DRM_EDID_YCBCR420_DC_30;
 		else
-			return info->edid_hdmi_dc_modes & DRM_EDID_HDMI_DC_30;
+			return info->edid_hdmi_rgb444_dc_modes & DRM_EDID_HDMI_DC_30;
 	case 8:
 		return true;
 	default:

drivers/gpu/drm/radeon/radeon_connectors.c

@@ -204,7 +204,7 @@ int radeon_get_monitor_bpc(struct drm_connector *connector)
 
 			/* Check if bpc is within clock limit. Try to degrade gracefully otherwise */
 			if ((bpc == 12) && (mode_clock * 3/2 > max_tmds_clock)) {
-				if ((connector->display_info.edid_hdmi_dc_modes & DRM_EDID_HDMI_DC_30) &&
+				if ((connector->display_info.edid_hdmi_rgb444_dc_modes & DRM_EDID_HDMI_DC_30) &&
 					(mode_clock * 5/4 <= max_tmds_clock))
 					bpc = 10;
 				else

include/drm/drm_connector.h

@@ -592,10 +592,16 @@ struct drm_display_info {
 	bool rgb_quant_range_selectable;
 
 	/**
-	 * @edid_hdmi_dc_modes: Mask of supported hdmi deep color modes. Even
-	 * more stuff redundant with @bus_formats.
+	 * @edid_hdmi_dc_rgb444_modes: Mask of supported hdmi deep color modes
+	 * in RGB 4:4:4. Even more stuff redundant with @bus_formats.
 	 */
-	u8 edid_hdmi_dc_modes;
+	u8 edid_hdmi_rgb444_dc_modes;
+
+	/**
+	 * @edid_hdmi_dc_ycbcr444_modes: Mask of supported hdmi deep color
+	 * modes in YCbCr 4:4:4. Even more stuff redundant with @bus_formats.
+	 */
+	u8 edid_hdmi_ycbcr444_dc_modes;
 
 	/**
 	 * @cea_rev: CEA revision of the HDMI sink.