drm/radeon: improve dvi_mode_valid

Make sure we have an HDMI monitor before validating modes with
clocks >165 Mhz on single link connections.
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/radeon_connectors.c

@@ -1288,18 +1288,16 @@ static int radeon_dvi_mode_valid(struct drm_connector *connector,
 		    (radeon_connector->connector_object_id == CONNECTOR_OBJECT_ID_DUAL_LINK_DVI_D) ||
 		    (radeon_connector->connector_object_id == CONNECTOR_OBJECT_ID_HDMI_TYPE_B))
 			return MODE_OK;
-		else if (radeon_connector->connector_object_id == CONNECTOR_OBJECT_ID_HDMI_TYPE_A) {
-			if (ASIC_IS_DCE6(rdev)) {
+		else if (ASIC_IS_DCE6(rdev) && drm_detect_hdmi_monitor(radeon_connector->edid)) {
 			/* HDMI 1.3+ supports max clock of 340 Mhz */
 			if (mode->clock > 340000)
 				return MODE_CLOCK_HIGH;
 			else
 				return MODE_OK;
-			} else
-				return MODE_CLOCK_HIGH;
-		} else
+		} else {
 			return MODE_CLOCK_HIGH;
 		}
+	}
 
 	/* check against the max pixel clock */
 	if ((mode->clock / 10) > rdev->clock.max_pixel_clock)