Index: uspace/lib/usbhost/include/usb/host/bus.h
===================================================================
--- uspace/lib/usbhost/include/usb/host/bus.h	(revision a5b3de686cf45ac7977c1c28f81da0a17ff37df8)
+++ uspace/lib/usbhost/include/usb/host/bus.h	(revision 5bc825040f32e2d34fc1a60dd0dbe3965ffda3d9)
@@ -82,4 +82,5 @@
 	int (*remove_device)(bus_t *, hcd_t *, device_t *);
 
+	/* The following operations are protected by a bus guard. */
 	endpoint_t *(*create_endpoint)(bus_t *);
 	int (*register_endpoint)(bus_t *, endpoint_t *, const usb_endpoint_desc_t *);