Index: sys/dev/cardbus/cardbus.c
===================================================================
--- sys/dev/cardbus/cardbus.c
+++ sys/dev/cardbus/cardbus.c
@@ -346,6 +346,7 @@
 	DEVMETHOD(bus_get_dma_tag,	bus_generic_get_dma_tag),
 	DEVMETHOD(bus_read_ivar,	cardbus_read_ivar),
 	DEVMETHOD(bus_driver_added,	cardbus_driver_added),
+	DEVMETHOD(bus_rescan,		kobj_error_method),
 
 	/* Card Interface */
 	DEVMETHOD(card_attach_card,	cardbus_attach_card),
Index: sys/dev/pci/pci.c
===================================================================
--- sys/dev/pci/pci.c
+++ sys/dev/pci/pci.c
@@ -168,6 +168,7 @@
 	DEVMETHOD(bus_remap_intr,	pci_remap_intr_method),
 	DEVMETHOD(bus_suspend_child,	pci_suspend_child),
 	DEVMETHOD(bus_resume_child,	pci_resume_child),
+	DEVMETHOD(bus_rescan,		pci_rescan_method),
 
 	/* PCI interface */
 	DEVMETHOD(pci_read_config,	pci_read_config_method),
@@ -3916,6 +3917,103 @@
 #undef REG
 }
 
+int
+pci_rescan_method(device_t dev)
+{
+#define	REG(n, w)	PCIB_READ_CONFIG(pcib, busno, s, f, n, w)
+	device_t pcib = device_get_parent(dev);
+	struct pci_softc *sc;
+	device_t child, *devlist, *unchanged;
+	int devcount, error, i, j, maxslots, oldcount;
+	int busno, domain, s, f, pcifunchigh;
+	uint8_t hdrtype;
+
+	/* No need to check for ARI on a rescan. */
+	error = device_get_children(dev, &devlist, &devcount);
+	if (error)
+		return (error);
+	if (devcount != 0) {
+		unchanged = malloc(devcount * sizeof(device_t), M_TEMP,
+		    M_NOWAIT | M_ZERO);
+		if (unchanged == NULL) {
+			free(devlist, M_TEMP);
+			return (ENOMEM);
+		}
+	} else
+		unchanged = NULL;
+
+	sc = device_get_softc(dev);
+	domain = pcib_get_domain(dev);
+	busno = pcib_get_bus(dev);
+	maxslots = PCIB_MAXSLOTS(pcib);
+	for (s = 0; s <= maxslots; s++) {
+		/* If function 0 is not present, skip to the next slot. */
+		f = 0;
+		if (REG(PCIR_VENDOR, 2) == 0xffff)
+			continue;
+		pcifunchigh = 0;
+		hdrtype = REG(PCIR_HDRTYPE, 1);
+		if ((hdrtype & PCIM_HDRTYPE) > PCI_MAXHDRTYPE)
+			continue;
+		if (hdrtype & PCIM_MFDEV)
+			pcifunchigh = PCIB_MAXFUNCS(pcib);
+		for (f = 0; f <= pcifunchigh; f++) {
+			if (REG(PCIR_VENDOR, 2) == 0xfff)
+				continue;
+
+			/*
+			 * Found a valid function.  Check if a
+			 * device_t for this device already exists.
+			 */
+			for (i = 0; i < devcount; i++) {
+				child = devlist[i];
+				if (child == NULL)
+					continue;
+				if (pci_get_slot(child) == s &&
+				    pci_get_function(child) == f) {
+					unchanged[i] = child;
+					goto next_func;
+				}
+			}
+
+			pci_identify_function(pcib, dev, domain, busno, s, f);
+		next_func:;
+		}
+	}
+
+	/* Remove devices that are no longer present. */
+	for (i = 0; i < devcount; i++) {
+		if (unchanged[i] != NULL)
+			continue;
+		device_delete_child(dev, devlist[i]);
+	}
+
+	free(devlist, M_TEMP);
+	oldcount = devcount;
+
+	/* Try to attach the devices just added. */
+	error = device_get_children(dev, &devlist, &devcount);
+	if (error) {
+		free(unchanged, M_TEMP);
+		return (error);
+	}
+
+	for (i = 0; i < devcount; i++) {
+		for (j = 0; j < oldcount; j++) {
+			if (devlist[i] == unchanged[j])
+				goto next_device;
+		}
+
+		device_probe_and_attach(devlist[i]);
+	next_device:;
+	}
+
+	free(unchanged, M_TEMP);
+	free(devlist, M_TEMP);
+	return (0);
+#undef REG
+}
+
 #ifdef PCI_IOV
 device_t
 pci_add_iov_child(device_t bus, device_t pf, uint16_t rid, uint16_t vid,
Index: sys/dev/pci/pci_private.h
===================================================================
--- sys/dev/pci/pci_private.h
+++ sys/dev/pci/pci_private.h
@@ -57,6 +57,7 @@
 void		pci_add_resources_ea(device_t bus, device_t dev, int alloc_iov);
 struct pci_devinfo *pci_alloc_devinfo_method(device_t dev);
 int		pci_attach_common(device_t dev);
+int		pci_rescan_method(device_t dev);
 void		pci_driver_added(device_t dev, driver_t *driver);
 int		pci_ea_is_enabled(device_t dev, int rid);
 int		pci_print_child(device_t dev, device_t child);
Index: sys/mips/nlm/xlp_pci.c
===================================================================
--- sys/mips/nlm/xlp_pci.c
+++ sys/mips/nlm/xlp_pci.c
@@ -154,6 +154,7 @@
 	/* Device interface */
 	DEVMETHOD(device_probe,		xlp_pci_probe),
 	DEVMETHOD(device_attach,	xlp_pci_attach),
+	DEVMETHOD(bus_rescan,		kobj_error_method),
 	DEVMETHOD_END
 };
 
Index: sys/powerpc/ofw/ofw_pcibus.c
===================================================================
--- sys/powerpc/ofw/ofw_pcibus.c
+++ sys/powerpc/ofw/ofw_pcibus.c
@@ -77,6 +77,7 @@
 	/* Bus interface */
 	DEVMETHOD(bus_child_deleted,	ofw_pcibus_child_deleted),
 	DEVMETHOD(bus_child_pnpinfo_str, ofw_pcibus_child_pnpinfo_str_method),
+	DEVMETHOD(bus_rescan,		kobj_error_method),
 
 	/* PCI interface */
 	DEVMETHOD(pci_alloc_devinfo,	ofw_pcibus_alloc_devinfo),
Index: sys/sparc64/pci/ofw_pcibus.c
===================================================================
--- sys/sparc64/pci/ofw_pcibus.c
+++ sys/sparc64/pci/ofw_pcibus.c
@@ -81,6 +81,7 @@
 	/* Bus interface */
 	DEVMETHOD(bus_child_deleted,	ofw_pcibus_child_deleted),
 	DEVMETHOD(bus_child_pnpinfo_str, ofw_pcibus_pnpinfo_str),
+	DEVMETHOD(bus_rescan,		kobj_error_method),
 
 	/* PCI interface */
 	DEVMETHOD(pci_alloc_devinfo,	ofw_pcibus_alloc_devinfo),