diff --git a/lib/XMonad/Internal/DBus/Brightness/Common.hs b/lib/XMonad/Internal/DBus/Brightness/Common.hs
index 2033ca5..7f336f4 100644
--- a/lib/XMonad/Internal/DBus/Brightness/Common.hs
+++ b/lib/XMonad/Internal/DBus/Brightness/Common.hs
@@ -114,7 +114,11 @@ brightnessExporter q ful deps bc@BrightnessConfig {bcName = n} cl =
     root = DBusRoot_ (exportBrightnessControls' bc) tree cl
     tree = listToAnds (Bus ful xmonadBusName) $ fmap DBusIO deps
 
-exportBrightnessControls' :: RealFrac b => BrightnessConfig a b -> SesClient -> FIO ()
+exportBrightnessControls'
+  :: (MonadUnliftIO m, RealFrac b)
+  => BrightnessConfig a b
+  -> SesClient
+  -> m ()
 exportBrightnessControls' bc cl = io $ do
   let ses = toClient cl
   maxval <- bcGetMax bc -- assume the max value will never change