Index: uspace/lib/c/generic/as.c
===================================================================
--- uspace/lib/c/generic/as.c	(revision 311bc25924dad9f6316e2c8e7e62c99664d1be2a)
+++ uspace/lib/c/generic/as.c	(revision 679a135a8e85dc7aaa42ab4a8385e31cdf47ac24)
@@ -35,4 +35,5 @@
 #include <as.h>
 #include <libc.h>
+#include <errno.h>
 #include <unistd.h>
 #include <align.h>
@@ -128,4 +129,30 @@
 }
 
+/** Find mapping to physical address.
+ *
+ * @param address Virtual address in question (virtual).
+ * @param[out] frame Frame address (physical).
+ * @return Error code.
+ * @retval EOK No error, @p frame holds the translation.
+ * @retval ENOENT Mapping not found.
+ */
+int as_get_physical_mapping(void *address, uintptr_t *frame)
+{
+	uintptr_t tmp_frame;
+	uintptr_t virt = (uintptr_t) address;
+	
+	int rc = (int) __SYSCALL2(SYS_PAGE_FIND_MAPPING,
+	    (sysarg_t) virt, (sysarg_t) &tmp_frame);
+	if (rc != EOK) {
+		return rc;
+	}
+	
+	if (frame != NULL) {
+		*frame = tmp_frame;
+	}
+	
+	return EOK;
+}
+
 /** @}
  */
Index: uspace/lib/c/include/as.h
===================================================================
--- uspace/lib/c/include/as.h	(revision 311bc25924dad9f6316e2c8e7e62c99664d1be2a)
+++ uspace/lib/c/include/as.h	(revision 679a135a8e85dc7aaa42ab4a8385e31cdf47ac24)
@@ -47,4 +47,5 @@
 extern void *set_maxheapsize(size_t mhs);
 extern void * as_get_mappable_page(size_t sz);
+extern int as_get_physical_mapping(void *address, uintptr_t *frame);
 
 #endif
Index: uspace/lib/c/include/assert.h
===================================================================
--- uspace/lib/c/include/assert.h	(revision 311bc25924dad9f6316e2c8e7e62c99664d1be2a)
+++ uspace/lib/c/include/assert.h	(revision 679a135a8e85dc7aaa42ab4a8385e31cdf47ac24)
@@ -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 311bc25924dad9f6316e2c8e7e62c99664d1be2a)
+++ uspace/lib/c/include/ipc/dev_iface.h	(revision 679a135a8e85dc7aaa42ab4a8385e31cdf47ac24)
@@ -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 311bc25924dad9f6316e2c8e7e62c99664d1be2a)
+++ uspace/lib/c/include/ipc/kbd.h	(revision 679a135a8e85dc7aaa42ab4a8385e31cdf47ac24)
@@ -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;