diff --git a/clutter/x11/clutter-device-manager-xi2.c b/clutter/x11/clutter-device-manager-xi2.c
index 03b0b4559..64f9eede7 100644
--- a/clutter/x11/clutter-device-manager-xi2.c
+++ b/clutter/x11/clutter-device-manager-xi2.c
@@ -650,9 +650,9 @@ scroll_valuators_changed (ClutterInputDevice *device,
 
           if (direction == CLUTTER_SCROLL_UP ||
               direction == CLUTTER_SCROLL_DOWN)
-            *dx_p = delta;
-          else
             *dy_p = delta;
+          else
+            *dx_p = delta;
         }
 
       n_val += 1;