Index: uspace/lib/c/generic/async/server.c
===================================================================
--- uspace/lib/c/generic/async/server.c	(revision 49a796f1d5e0783f179376793f1b84d4f6cf0bde)
+++ uspace/lib/c/generic/async/server.c	(revision c8afd5a8029517aba09c3f07e907308d90b306a2)
@@ -125,5 +125,5 @@
 
 /** Number of threads waiting for IPC in the kernel. */
-atomic_t threads_in_ipc_wait = { 0 };
+static atomic_t threads_in_ipc_wait = { 0 };
 
 /** Call data */
@@ -1273,5 +1273,6 @@
 void async_poke(void)
 {
-	ipc_poke();
+	if (atomic_get(&threads_in_ipc_wait) > 0)
+		ipc_poke();
 }