drm/edid: split CTA Y420VDB info and mode parsing

Separate the parsing of display info and modes from the CTA
Y420VDB. This is prerequisite work for overall better separation of the
two parsing steps.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/3bc5fe6650a6ce4249803f7192096764ea724e05.1672826282.git.jani.nikula@intel.com

drivers/gpu/drm/drm_edid.c

@@ -4497,10 +4497,8 @@ drm_display_mode_from_vic_index(struct drm_connector *connector, int vic_index)
 static int do_y420vdb_modes(struct drm_connector *connector,
 			    const u8 *svds, u8 svds_len)
 {
-	int modes = 0, i;
 	struct drm_device *dev = connector->dev;
-	struct drm_display_info *info = &connector->display_info;
-	struct drm_hdmi_info *hdmi = &info->hdmi;
+	int modes = 0, i;
 
 	for (i = 0; i < svds_len; i++) {
 		u8 vic = svd_to_vic(svds[i]);
@@ -4512,13 +4510,10 @@ static int do_y420vdb_modes(struct drm_connector *connector,
 		newmode = drm_mode_duplicate(dev, cea_mode_for_vic(vic));
 		if (!newmode)
 			break;
-		bitmap_set(hdmi->y420_vdb_modes, vic, 1);
 		drm_mode_probed_add(connector, newmode);
 		modes++;
 	}
 
-	if (modes > 0)
-		info->color_formats |= DRM_COLOR_FORMAT_YCBCR420;
 	return modes;
 }
 
@@ -5876,6 +5871,26 @@ static bool cta_vdb_has_vic(const struct drm_connector *connector, u8 vic)
 	return false;
 }
 
+/* CTA-861-H YCbCr 4:2:0 Video Data Block (CTA Y420VDB) */
+static void parse_cta_y420vdb(struct drm_connector *connector,
+			      const struct cea_db *db)
+{
+	struct drm_display_info *info = &connector->display_info;
+	struct drm_hdmi_info *hdmi = &info->hdmi;
+	const u8 *svds = cea_db_data(db) + 1;
+	int i;
+
+	for (i = 0; i < cea_db_payload_len(db) - 1; i++) {
+		u8 vic = svd_to_vic(svds[i]);
+
+		if (!drm_valid_cea_vic(vic))
+			continue;
+
+		bitmap_set(hdmi->y420_vdb_modes, vic, 1);
+		info->color_formats |= DRM_COLOR_FORMAT_YCBCR420;
+	}
+}
+
 static void drm_parse_vcdb(struct drm_connector *connector, const u8 *db)
 {
 	struct drm_display_info *info = &connector->display_info;
@@ -6216,6 +6231,8 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
 			drm_parse_microsoft_vsdb(connector, data);
 		else if (cea_db_is_y420cmdb(db))
 			parse_cta_y420cmdb(connector, db, &y420cmdb_map);
+		else if (cea_db_is_y420vdb(db))
+			parse_cta_y420vdb(connector, db);
 		else if (cea_db_is_vcdb(db))
 			drm_parse_vcdb(connector, data);
 		else if (cea_db_is_hdmi_hdr_metadata_block(db))