Index: uspace/lib/c/include/ipc/dev_iface.h
===================================================================
--- uspace/lib/c/include/ipc/dev_iface.h	(revision cb59f787f3b39c1da8220eb8042b8c459a038c61)
+++ uspace/lib/c/include/ipc/dev_iface.h	(revision ae1f70ec89abbdbd299b59710e8ae5be5f7e3505)
@@ -54,4 +54,14 @@
 	DEV_IFACE_ID(DEV_FIRST_CUSTOM_METHOD_IDX)
 
+/*
+ * The first argument is actually method (as the "real" method is used
+ * for indexing into interfaces.
+ */
+
+#define DEV_IPC_GET_ARG1(call) IPC_GET_ARG2((call))
+#define DEV_IPC_GET_ARG2(call) IPC_GET_ARG3((call))
+#define DEV_IPC_GET_ARG3(call) IPC_GET_ARG4((call))
+#define DEV_IPC_GET_ARG4(call) IPC_GET_ARG5((call))
+
 
 #endif