Index: uspace/lib/c/generic/devman.c
===================================================================
--- uspace/lib/c/generic/devman.c	(revision 774e6d1abebc631f873d85e623bf7aa61b0aecea)
+++ uspace/lib/c/generic/devman.c	(revision f40a1e24252e9904e01ba889c8b1edbbe5cc9d63)
@@ -85,5 +85,4 @@
 			devman_phone_client = async_connect_me_to(PHONE_NS,
 			    SERVICE_DEVMAN, DEVMAN_CLIENT, 0);
-			fibril_mutex_unlock(&devman_phone_mutex);
 		
 		fibril_mutex_unlock(&devman_phone_mutex);
Index: uspace/lib/c/include/assert.h
===================================================================
--- uspace/lib/c/include/assert.h	(revision 774e6d1abebc631f873d85e623bf7aa61b0aecea)
+++ uspace/lib/c/include/assert.h	(revision f40a1e24252e9904e01ba889c8b1edbbe5cc9d63)
@@ -57,4 +57,6 @@
 			printf("Assertion failed (%s) at file '%s', " \
 			    "line %d.\n", #expr, __FILE__, __LINE__); \
+			stacktrace_print(); \
+			core(); \
 			abort(); \
 		} \
Index: uspace/lib/c/include/ipc/dev_iface.h
===================================================================
--- uspace/lib/c/include/ipc/dev_iface.h	(revision 774e6d1abebc631f873d85e623bf7aa61b0aecea)
+++ uspace/lib/c/include/ipc/dev_iface.h	(revision f40a1e24252e9904e01ba889c8b1edbbe5cc9d63)
@@ -38,4 +38,10 @@
 	HW_RES_DEV_IFACE = 0,
 	CHAR_DEV_IFACE,
+
+	/** Interface provided by any USB device. */
+	USB_DEV_IFACE,
+	/** Interface provided by USB host controller. */
+	USBHC_DEV_IFACE,
+
 	DEV_IFACE_MAX
 } dev_inferface_idx_t;
@@ -49,4 +55,14 @@
 	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
Index: uspace/lib/c/include/ipc/kbd.h
===================================================================
--- uspace/lib/c/include/ipc/kbd.h	(revision 774e6d1abebc631f873d85e623bf7aa61b0aecea)
+++ uspace/lib/c/include/ipc/kbd.h	(revision f40a1e24252e9904e01ba889c8b1edbbe5cc9d63)
@@ -39,7 +39,8 @@
 
 #include <ipc/ipc.h>
+#include <ipc/dev_iface.h>
 
 typedef enum {
-	KBD_YIELD = IPC_FIRST_USER_METHOD,
+	KBD_YIELD = DEV_FIRST_CUSTOM_METHOD,
 	KBD_RECLAIM
 } kbd_request_t;