Index: uspace/lib/usbdev/src/pipes.c
===================================================================
--- uspace/lib/usbdev/src/pipes.c	(revision 8582076f97c2ef5e9cb3b8f6d18a7abc8915260c)
+++ uspace/lib/usbdev/src/pipes.c	(revision 11e9e6132d3c81fa01d6598f5fda6b450cc5d20e)
@@ -318,9 +318,13 @@
 {
 	assert(pipe);
-	assert(pipe->wire);
-
-	return usb_device_register_endpoint(pipe->wire,
-	   pipe->endpoint_no, pipe->transfer_type,
-	   pipe->direction, pipe->max_packet_size, interval);
+	assert(pipe->bus_session);
+	async_exch_t *exch = async_exchange_begin(pipe->bus_session);
+	if (!exch)
+		return ENOMEM;
+	const int ret = usb_register_endpoint(exch, pipe->endpoint_no,
+	    pipe->transfer_type, pipe->direction, pipe->max_packet_size,
+	    interval);
+	async_exchange_end(exch);
+	return ret;
 }
 
@@ -333,8 +337,12 @@
 {
 	assert(pipe);
-	assert(pipe->wire);
-
-	return usb_device_unregister_endpoint(pipe->wire,
-	    pipe->endpoint_no, pipe->direction);
+	assert(pipe->bus_session);
+	async_exch_t *exch = async_exchange_begin(pipe->bus_session);
+	if (!exch)
+		return ENOMEM;
+	const int ret = usb_unregister_endpoint(exch, pipe->endpoint_no,
+	    pipe->direction);
+	async_exchange_end(exch);
+	return ret;
 }