--- sys/kern/subr_bus.c.orig	2009-09-21 00:27:09.000000000 +0200
+++ sys/kern/subr_bus.c	2009-09-21 00:33:43.000000000 +0200
@@ -2953,7 +2953,9 @@
 	device_t child;
 
 	TAILQ_FOREACH(child, &dev->children, link) {
+	        printf(">>> DEVICE '%s'\n", child->nameunit==NULL?"<NULL>":child->nameunit);
 		device_shutdown(child);
+	        printf("<<< DEVICE RETURN"\n);
 	}
 
 	return (0);