Index: lib/libdevctl/devctl.h
===================================================================
--- lib/libdevctl/devctl.h
+++ lib/libdevctl/devctl.h
@@ -41,5 +41,7 @@
 int	devctl_clear_driver(const char *device, bool force);
 int	devctl_rescan(const char *device);
 int	devctl_delete(const char *device, bool force);
+int	devctl_freeze(void);
+int	devctl_thaw(void);
 
 #endif /* !__DEVCTL_H__ */
Index: lib/libdevctl/devctl.3
===================================================================
--- lib/libdevctl/devctl.3
+++ lib/libdevctl/devctl.3
@@ -36,10 +36,12 @@
 .Nm devctl_detach ,
 .Nm devctl_disable ,
 .Nm devctl_enable ,
+.Nm devctl_freeze ,
 .Nm devctl_rescan ,
 .Nm devctl_resume ,
 .Nm devctl_set_driver ,
-.Nm devctl_suspend
+.Nm devctl_suspend ,
+.Nm devctl_thaw
 .Nd device control library
 .Sh LIBRARY
 .Lb libdevctl
@@ -58,6 +60,8 @@
 .Ft int
 .Fn devctl_enable "const char *device"
 .Ft int
+.Fn devctl_freeze "void"
+.Ft int
 .Fn devctl_rescan "const char *device"
 .Ft int
 .Fn devctl_resume "const char *device"
@@ -65,6 +69,8 @@
 .Fn devctl_set_driver "const char *device" "const char *driver" "bool force"
 .Ft int
 .Fn devctl_suspend "const char *device"
+.Ft int
+.Fn devctl_thaw "void"
 .Sh DESCRIPTION
 The
 .Nm
@@ -189,6 +195,16 @@
 .Fn devctl_rescan
 function rescans a bus device checking for devices that have been added or
 removed.
+.Pp
+The
+.Fn devctl_freeze
+function freezes probe and attach processing initiated in response to
+drivers being loaded.
+.Pp
+The
+.Fn devctl_thaw
+function resumes (thaws the freeze) probe and attach processing
+initiated in response to drivers being loaded.
 .Sh RETURN VALUES
 .Rv -std devctl_attach devctl_clear_driver devctl_delete devctl_detach \
 devctl_disable devctl_enable devctl_suspend devctl_rescan devctl_resume \
Index: lib/libdevctl/devctl.c
===================================================================
--- lib/libdevctl/devctl.c
+++ lib/libdevctl/devctl.c
@@ -53,7 +53,7 @@
 	struct devreq req;
 
 	memset(&req, 0, sizeof(req));
-	if (strlcpy(req.dr_name, name, sizeof(req.dr_name)) >=
+	if (name != NULL && strlcpy(req.dr_name, name, sizeof(req.dr_name)) >=
 	    sizeof(req.dr_name)) {
 		errno = EINVAL;
 		return (-1);
@@ -145,3 +145,17 @@
 	return (devctl_simple_request(DEV_DELETE, device, force ?
 	    DEVF_FORCE_DELETE : 0));
 }
+
+int
+devctl_freeze(void)
+{
+
+	return (devctl_simple_request(DEV_FREEZE, NULL, 0));
+}
+
+int
+devctl_thaw(void)
+{
+
+	return (devctl_simple_request(DEV_THAW, NULL, 0));
+}
Index: sbin/devmatch/devmatch.c
===================================================================
--- sbin/devmatch/devmatch.c
+++ sbin/devmatch/devmatch.c
@@ -56,12 +56,6 @@
 
 #define	DEVMATCH_MAX_HITS 256
 
-static struct match_data {
-	char *descr;
-	int priority;
-} match_data[DEVMATCH_MAX_HITS];
-
-static int hit_index;
 static int all_flag;
 static int dump_flag;
 static char *linker_hints;
@@ -240,35 +234,6 @@
 	return retval;
 }
 
-static int
-match_data_compare(const void *_pa, const void *_pb)
-{
-	const struct match_data *pa = _pa;
-	const struct match_data *pb = _pb;
-
-	/* biggest value first */
-	if (pa->priority > pb->priority)
-		return (-1);
-	else if (pa->priority < pb->priority)
-		return (1);
-
-	/* then sort by string */
-	return (strcmp(pa->descr, pb->descr));
-}
-
-static int
-bitrev16(int input)
-{
-	int retval = 0;
-	int x;
-
-	for (x = 0; x != 16; x++) {
-		if ((input >> x) & 1)
-			retval |= (0x8000 >> x);
-	}
-	return (retval);
-}
-
 static void
 search_hints(const char *bus, const char *dev, const char *pnpinfo)
 {
@@ -417,22 +382,12 @@
 					printf("\n");
 				else if (!notme) {
 					if (!unbound_flag) {
-						char *descr = NULL;
-
 						if (all_flag)
-							asprintf(&descr, "%s: %s", *dev ? dev : "unattached", lastmod);
+							printf("%s: %s", *dev ? dev : "unattached", lastmod);
 						else
-							asprintf(&descr, "%s", lastmod);
+							printf("%s", lastmod);
 						if (verbose_flag)
 							printf("Matches --- %s ---\n", lastmod);
-
-						if (descr != NULL && hit_index < DEVMATCH_MAX_HITS) {
-							match_data[hit_index].descr = descr;
-							match_data[hit_index].priority = bitrev16(mask);
-							hit_index++;
-						} else {
-							free(descr);
-						}
 					}
 					found++;
 				}
@@ -445,19 +400,6 @@
 		}
 		walker = (void *)(len - sizeof(int) + (intptr_t)walker);
 	}
-	if (hit_index != 0) {
-		/* sort hits by priority */
-		mergesort(match_data, hit_index, sizeof(match_data[0]), &match_data_compare);
-
-		/* printout */
-		for (i = 0; i != hit_index; i++) {
-			puts(match_data[i].descr);
-			free(match_data[i].descr);
-		}
-
-		/* reset hit_index */
-		hit_index = 0;
-	}       
 	if (unbound_flag && found == 0 && *pnpinfo) {
 		if (verbose_flag)
 			printf("------------------------- ");
Index: sbin/init/rc.d/devmatch
===================================================================
--- sbin/init/rc.d/devmatch
+++ sbin/init/rc.d/devmatch
@@ -44,9 +44,9 @@
 	local x
 
 	if [ -n "$one_nomatch" ]; then
-		x=$(devmatch -p "${one_nomatch}")
+		x=$(devmatch -p "${one_nomatch}" | sort -u)
 	else
-		x=$(devmatch)
+		x=$(devmatch | sort -u)
 	fi
 
 	[ -n "$x" ] || return
@@ -57,10 +57,12 @@
 	# We also optimize against the false positives
 	# or drivers that have symbolic links that
 	# confuse devmatch by running it -n.
+	devctl freeze
 	for m in ${x}; do
 		echo "Autoloading module: ${m}"
 		kldload -n ${m}
 	done
+	devctl thaw
 }
 
 load_rc_config $name
Index: sys/kern/subr_bus.c
===================================================================
--- sys/kern/subr_bus.c
+++ sys/kern/subr_bus.c
@@ -82,6 +82,8 @@
 	kobj_class_t	driver;
 	TAILQ_ENTRY(driverlink) link;	/* list of drivers in devclass */
 	int		pass;
+	int		flags;
+#define DL_DEFERRED_PROBE	1	/* Probe deferred on this */
 	TAILQ_ENTRY(driverlink) passlink;
 };
 
@@ -101,6 +103,7 @@
 	int		maxunit;	/* size of devices array */
 	int		flags;
 #define DC_HAS_CHILDREN		1
+#define DC_DEFERRED_PROBE	2	/* Driver loaded during freeze */
 
 	struct sysctl_ctx_list sysctl_ctx;
 	struct sysctl_oid *sysctl_tree;
@@ -152,6 +155,7 @@
 EVENTHANDLER_LIST_DEFINE(dev_lookup);
 
 static void devctl2_init(void);
+static bool device_frozen;
 
 #define DRIVERNAME(d)	((d)? d->name : "no driver")
 #define DEVCLANAME(d)	((d)? d->name : "no devclass")
@@ -1168,7 +1172,12 @@
 	dl->pass = pass;
 	driver_register_pass(dl);
 
-	devclass_driver_added(dc, driver);
+	if (device_frozen) {
+		dc->flags |= DC_DEFERRED_PROBE;
+		dl->flags |= DL_DEFERRED_PROBE;
+	} else {
+		devclass_driver_added(dc, driver);
+	}
 	bus_data_generation_update();
 	return (0);
 }
@@ -5406,6 +5415,26 @@
 	return (false);
 }
 
+static void
+device_do_deferred_probes(void)
+{
+	devclass_t dc;
+	driverlink_t dl;
+
+	TAILQ_FOREACH(dc, &devclasses, link) {
+		if ((dc->flags & DC_DEFERRED_PROBE) == 0)
+			continue;
+		TAILQ_FOREACH(dl, &dc->drivers, link) {
+			if ((dl->flags & DL_DEFERRED_PROBE) == 0)
+				continue;
+			devclass_driver_added(dc, dl->driver);
+			dl->flags &= ~DL_DEFERRED_PROBE;
+		}
+		dc->flags &= ~DC_DEFERRED_PROBE;
+	}
+	bus_data_generation_update();
+}
+
 static int
 devctl2_ioctl(struct cdev *cdev, u_long cmd, caddr_t data, int fflag,
     struct thread *td)
@@ -5432,6 +5461,10 @@
 		if (error == 0)
 			error = find_device(req, &dev);
 		break;
+	case DEV_FREEZE:
+	case DEV_THAW:
+		error = priv_check(td, PRIV_DRIVER);
+		break;
 	default:
 		error = ENOTTY;
 		break;
@@ -5635,6 +5668,24 @@
 		error = device_delete_child(parent, dev);
 		break;
 	}
+	case DEV_FREEZE:
+		printf("Freeze: %d -- ", device_frozen);
+		if (device_frozen)
+			error = EBUSY;
+		else
+			device_frozen = true;
+		printf("%d (%d)\n", device_frozen, error);
+		break;
+	case DEV_THAW:
+		printf("Thaw: %d -- ", device_frozen);
+		if (!device_frozen)
+			error = EBUSY;
+		else {
+			device_do_deferred_probes();
+			device_frozen = false;
+		}
+		printf("%d (%d)\n", device_frozen, error);
+		break;
 	}
 	mtx_unlock(&Giant);
 	return (error);
Index: sys/sys/bus.h
===================================================================
--- sys/sys/bus.h
+++ sys/sys/bus.h
@@ -126,6 +126,8 @@
 #define	DEV_CLEAR_DRIVER _IOW('D', 8, struct devreq)
 #define	DEV_RESCAN	_IOW('D', 9, struct devreq)
 #define	DEV_DELETE	_IOW('D', 10, struct devreq)
+#define	DEV_FREEZE	_IOW('D', 11, struct devreq)
+#define	DEV_THAW	_IOW('D', 12, struct devreq)
 
 /* Flags for DEV_DETACH and DEV_DISABLE. */
 #define	DEVF_FORCE_DETACH	0x0000001
Index: usr.sbin/devctl/devctl.c
===================================================================
--- usr.sbin/devctl/devctl.c
+++ usr.sbin/devctl/devctl.c
@@ -71,17 +71,19 @@
 static void
 usage(void)
 {
-	fprintf(stderr, "%s\n%s\n%s\n%s\n%s\n%s\n%s\n%s\n%s\n%s\n",
-	    "usage: devctl attach device",
-	    "       devctl detach [-f] device",
-	    "       devctl disable [-f] device",
-	    "       devctl enable device",
-	    "       devctl suspend device",
-	    "       devctl resume device",
-	    "       devctl set driver [-f] device driver",
-	    "       devctl clear driver [-f] device",
-	    "       devctl rescan device",
-	    "       devctl delete [-f] device");
+	fprintf(stderr,
+	    "usage: devctl attach device\n"
+	    "       devctl detach [-f] device\n"
+	    "       devctl disable [-f] device\n"
+	    "       devctl enable device\n"
+	    "       devctl suspend device\n"
+	    "       devctl resume device\n"
+	    "       devctl set driver [-f] device driver\n"
+	    "       devctl clear driver [-f] device\n"
+	    "       devctl rescan device\n"
+	    "       devctl delete [-f] device\n"
+	    "       devctl freeze\n"
+	    "       devctl thaw\n");
 	exit(1);
 }
 
@@ -343,6 +345,46 @@
 }
 DEVCTL_COMMAND(top, delete, delete);
 
+static void
+freeze_usage(void)
+{
+
+	fprintf(stderr, "usage: devctl freeze\n");
+	exit(1);
+}
+
+static int
+freeze(int ac, char **av __unused)
+{
+
+	if (ac != 1)
+		freeze_usage();
+	if (devctl_freeze() < 0)
+		err(1, "Failed to freeze probe/attach");
+	return (0);
+}
+DEVCTL_COMMAND(top, freeze, freeze);
+
+static void
+thaw_usage(void)
+{
+
+	fprintf(stderr, "usage: devctl thaw\n");
+	exit(1);
+}
+
+static int
+thaw(int ac, char **av __unused)
+{
+
+	if (ac != 1)
+		thaw_usage();
+	if (devctl_thaw() < 0)
+		err(1, "Failed to thaw probe/attach");
+	return (0);
+}
+DEVCTL_COMMAND(top, thaw, thaw);
+
 int
 main(int ac, char *av[])
 {