Index: uspace/lib/drv/generic/driver.c
===================================================================
--- uspace/lib/drv/generic/driver.c	(revision 09ab0a9afc9379f1604c0fd75cac2d9287ba022c)
+++ uspace/lib/drv/generic/driver.c	(revision 889cdb1c2046af9d31d314fa691773fa2e4f9119)
@@ -345,6 +345,8 @@
 		async_get_call(&call);
 
-		if (!IPC_GET_IMETHOD(call))
+		if (!IPC_GET_IMETHOD(call)) {
+			async_answer_0(&call, EOK);
 			break;
+		}
 
 		switch (IPC_GET_IMETHOD(call)) {