drm: Only print a debug message when the polled connector has changed

Suggested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_crtc_helper.c

@@ -1007,14 +1007,21 @@ static void output_poll_execute(struct work_struct *work)
 			continue;
 
 		connector->status = connector->funcs->detect(connector, false);
-		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] status updated from %s to %s\n",
+		if (old_status != connector->status) {
+			const char *old, *new;
+
+			old = drm_get_connector_status_name(old_status);
+			new = drm_get_connector_status_name(connector->status);
+
+			DRM_DEBUG_KMS("[CONNECTOR:%d:%s] "
+				      "status updated from %s to %s\n",
 				      connector->base.id,
 				      drm_get_connector_name(connector),
-			      drm_get_connector_status_name(old_status),
-			      drm_get_connector_status_name(connector->status));
-		if (old_status != connector->status)
+				      old, new);
+
 			changed = true;
 		}
+	}
 
 	mutex_unlock(&dev->mode_config.mutex);