Index: uspace/lib/usbvirt/include/usbvirt/device.h
===================================================================
--- uspace/lib/usbvirt/include/usbvirt/device.h	(revision a9431063c7daebc88e60dea71fc147ee9b1fda01)
+++ uspace/lib/usbvirt/include/usbvirt/device.h	(revision dc06caa563afa95e8dd424ec2cee7abef3a78d47)
@@ -86,5 +86,9 @@
     uint8_t *data, size_t *act_data_size);
 
-/** Callback for control request on a virtual USB device. */
+/** Callback for control request on a virtual USB device.
+ *
+ * See usbvirt_control_reply_helper() for simple way of answering
+ * control read requests.
+ */
 typedef struct {
 	/** Request direction (in or out). */