diff --git a/selfdrive/ui/qt/window.cc b/selfdrive/ui/qt/window.cc
index 37174ae74..e9dbd2189 100644
--- a/selfdrive/ui/qt/window.cc
+++ b/selfdrive/ui/qt/window.cc
@@ -107,7 +107,7 @@ void GLWindow::timerUpdate(){
   }
 #endif
 
-  std::async(std::launch::async,
+  auto f = std::async(std::launch::async,
              [brightness]{
                std::ofstream brightness_control("/sys/class/backlight/panel0-backlight/brightness");
                if (brightness_control.is_open()){