Index: uspace/lib/hound/src/protocol.c
===================================================================
--- uspace/lib/hound/src/protocol.c	(revision 6133470b77e0c859395a7aded61ec6750499588d)
+++ uspace/lib/hound/src/protocol.c	(revision d988ef2a47fc17216b02595ca71934247ff2ce63)
@@ -511,5 +511,13 @@
 	ipc_call_t call;
 	size_t size = 0;
-	while (async_data_read_receive_call(&callid, &call, &size)) {
+	while (async_data_read_receive_call(&callid, &call, &size)
+	    || (IPC_GET_IMETHOD(call) == IPC_M_HOUND_STREAM_DRAIN)) {
+		if (IPC_GET_IMETHOD(call) == IPC_M_HOUND_STREAM_DRAIN) {
+			int ret = ENOTSUP;
+			if (server_iface->drain_stream)
+				ret = server_iface->drain_stream(stream);
+			async_answer_0(callid, ret);
+			continue;
+		}
 		char *buffer = malloc(size);
 		if (!buffer) {