diff --git a/module_usb_midi/src/usb_midi.xc b/module_usb_midi/src/usb_midi.xc
index 3b471c12..4b16efe7 100644
--- a/module_usb_midi/src/usb_midi.xc
+++ b/module_usb_midi/src/usb_midi.xc
@@ -353,7 +353,7 @@ void usb_midi(buffered in port:1 ?p_midi_in, port ?p_midi_out,
 
                 /* Slow timer looking for IDevice plug/unplug event */
                 case iAPTimer when timerafter(polltime) :> void:
-                    if (!iap_handle_poll_dev_det(iAPTimer))
+                    if (!iap_handle_poll_dev_det(iap_incoming_buffer, iap_outgoing_buffer))
                     {
                         check_iAP_timeout(iap_outgoing_buffer, c_iap);
                     }