Index: uspace/srv/devmap/devmap.c
===================================================================
--- uspace/srv/devmap/devmap.c	(revision 228e490270cec3d6a6de666f61839f0d9ed5f193)
+++ uspace/srv/devmap/devmap.c	(revision 6e50466ff28e9edcba1f6e48348d531d12cd5e38)
@@ -99,4 +99,6 @@
 	/** Device driver handling this device */
 	devmap_driver_t *driver;
+	/** Use this interface when forwarding to driver. */
+	sysarg_t forward_interface;
 } devmap_device_t;
 
@@ -517,4 +519,7 @@
 	}
 	
+	/* Set the interface, if any. */
+	device->forward_interface = IPC_GET_ARG1(*icall);
+
 	/* Get fqdn */
 	char *fqdn;
@@ -566,5 +571,5 @@
 	/* Get unique device handle */
 	device->handle = devmap_create_handle();
-	
+
 	devmap_namespace_addref(namespace, device);
 	device->driver = driver;
@@ -617,6 +622,16 @@
 	}
 	
-	ipc_forward_fast(callid, dev->driver->phone, dev->handle,
-	    IPC_GET_ARG3(*call), 0, IPC_FF_NONE);
+	if (dev->forward_interface == 0) {
+		/* The IPC_GET_ARG3(*icall) would be always zero,
+		 * wouldn't it? So why to pass it at all?
+		 */
+		ipc_forward_fast(callid, dev->driver->phone,
+		    dev->handle, 0, 0,
+		    IPC_FF_NONE);
+	} else {
+		ipc_forward_fast(callid, dev->driver->phone,
+		    dev->forward_interface, dev->handle, 0,
+		    IPC_FF_NONE);
+	}
 	
 	fibril_mutex_unlock(&devices_list_mutex);