Index: sys/dev/acpica/acpi_pcib_pci.c
===================================================================
--- sys/dev/acpica/acpi_pcib_pci.c
+++ sys/dev/acpica/acpi_pcib_pci.c
@@ -66,6 +66,7 @@
 
 static int		acpi_pcib_pci_probe(device_t bus);
 static int		acpi_pcib_pci_attach(device_t bus);
+static int		acpi_pcib_pci_detach(device_t bus);
 static int		acpi_pcib_read_ivar(device_t dev, device_t child,
 			    int which, uintptr_t *result);
 static int		acpi_pcib_pci_route_interrupt(device_t pcib,
@@ -75,6 +76,7 @@
     /* Device interface */
     DEVMETHOD(device_probe,		acpi_pcib_pci_probe),
     DEVMETHOD(device_attach,		acpi_pcib_pci_attach),
+    DEVMETHOD(device_detach,		acpi_pcib_pci_detach),
 
     /* Bus interface */
     DEVMETHOD(bus_read_ivar,		acpi_pcib_read_ivar),
@@ -127,6 +129,21 @@
 }
 
 static int
+acpi_pcib_pci_detach(device_t dev)
+{
+    struct acpi_pcib_softc *sc;
+    int error;
+
+    ACPI_FUNCTION_TRACE((char *)(uintptr_t)__func__);
+
+    sc = device_get_softc(dev);
+    error = pcib_detach(dev);
+    if (error == 0)
+	    AcpiOsFree(sc->ap_prt.Pointer);
+    return (error);
+}
+
+static int
 acpi_pcib_read_ivar(device_t dev, device_t child, int which, uintptr_t *result)
 {
     struct acpi_pcib_softc *sc = device_get_softc(dev);
Index: sys/dev/pccbb/pccbb_pci.c
===================================================================
--- sys/dev/pccbb/pccbb_pci.c
+++ sys/dev/pccbb/pccbb_pci.c
@@ -435,6 +435,22 @@
 	return (ENOMEM);
 }
 
+static int
+cbb_pci_detach(device_t brdev)
+{
+#if defined(NEW_PCIB) && defined(PCI_RES_BUS)
+	struct cbb_softc *sc = device_get_softc(brdev);
+#endif
+	int error;
+
+	error = cbb_detach(brdev);
+#if defined(NEW_PCIB) && defined(PCI_RES_BUS)
+	if (error == 0)
+		pcib_free_secbus(brdev, &sc->bus);
+#endif
+	return (error);
+}
+
 static void
 cbb_chipinit(struct cbb_softc *sc)
 {
@@ -917,7 +933,7 @@
 	/* Device interface */
 	DEVMETHOD(device_probe,			cbb_pci_probe),
 	DEVMETHOD(device_attach,		cbb_pci_attach),
-	DEVMETHOD(device_detach,		cbb_detach),
+	DEVMETHOD(device_detach,		cbb_pci_detach),
 	DEVMETHOD(device_shutdown,		cbb_pci_shutdown),
 	DEVMETHOD(device_suspend,		cbb_pci_suspend),
 	DEVMETHOD(device_resume,		cbb_pci_resume),
Index: sys/dev/pci/pci_pci.c
===================================================================
--- sys/dev/pci/pci_pci.c
+++ sys/dev/pci/pci_pci.c
@@ -80,7 +80,7 @@
     /* Device interface */
     DEVMETHOD(device_probe,		pcib_probe),
     DEVMETHOD(device_attach,		pcib_attach),
-    DEVMETHOD(device_detach,		bus_generic_detach),
+    DEVMETHOD(device_detach,		pcib_detach),
     DEVMETHOD(device_shutdown,		bus_generic_shutdown),
     DEVMETHOD(device_suspend,		pcib_suspend),
     DEVMETHOD(device_resume,		pcib_resume),
@@ -543,6 +543,42 @@
 	}
 }
 
+static void
+pcib_release_window(struct pcib_softc *sc, struct pcib_window *w, int type)
+{
+	device_t dev;
+	int error, i;
+
+	if (!w->valid)
+		return;
+
+	dev = sc->dev;
+	error = rman_fini(&w->rman);
+	if (error) {
+		device_printf(dev, "failed to release %s rman\n", w->name);
+		return;
+	}
+	free(__DECONST(char *, w->rman.rm_descr), M_DEVBUF);
+
+	for (i = 0; i < w->count; i++) {
+		error = bus_free_resource(dev, type, w->res[i]);
+		if (error)
+			device_printf(dev,
+			    "failed to release %s resource: %d\n", w->name,
+			    error);
+	}
+	free(w->res, M_DEVBUF);
+}
+
+static void
+pcib_free_windows(struct pcib_softc *sc)
+{
+
+	pcib_release_window(sc, &sc->pmem, SYS_RES_MEMORY);
+	pcib_release_window(sc, &sc->mem, SYS_RES_MEMORY);
+	pcib_release_window(sc, &sc->io, SYS_RES_IOPORT);
+}
+
 #ifdef PCI_RES_BUS
 /*
  * Allocate a suitable secondary bus for this bridge if needed and
@@ -617,6 +653,24 @@
 	}
 }
 
+void
+pcib_free_secbus(device_t dev, struct pcib_secbus *bus)
+{
+	int error;
+
+	error = rman_fini(&bus->rman);
+	if (error) {
+		device_printf(dev, "failed to release bus number rman\n");
+		return;
+	}
+	free(__DECONST(char *, bus->rman.rm_descr), M_DEVBUF);
+
+	error = bus_free_resource(dev, PCI_RES_BUS, bus->res);
+	if (error)
+		device_printf(dev,
+		    "failed to release bus numbers resource: %d\n", error);
+}
+
 static struct resource *
 pcib_suballoc_bus(struct pcib_secbus *bus, device_t child, int *rid,
     rman_res_t start, rman_res_t end, rman_res_t count, u_int flags)
@@ -1263,6 +1317,22 @@
 	return (0);
 }
 
+static int
+pcib_release_pcie_irq(struct pcib_softc *sc)
+{
+	device_t dev;
+	int error;
+
+	dev = sc->dev;
+	error = bus_teardown_intr(dev, sc->pcie_irq, sc->pcie_ihand);
+	if (error)
+		return (error);
+	error = bus_free_resource(dev, SYS_RES_IRQ, sc->pcie_irq);
+	if (error)
+		return (error);
+	return (pci_release_msi(dev));
+}
+
 static void
 pcib_setup_hotplug(struct pcib_softc *sc)
 {
@@ -1306,6 +1376,21 @@
 
 	pcib_pcie_hotplug_update(sc, val, mask, false);
 }
+
+static int
+pcib_detach_hotplug(struct pcib_softc *sc)
+{
+	int error;
+
+	error = pcib_release_pcie_irq(sc);
+	if (error)
+		return (error);
+	taskqueue_drain(taskqueue_thread, &sc->pcie_hp_task);
+	callout_drain(&sc->pcie_ab_timer);
+	callout_drain(&sc->pcie_cc_timer);
+	callout_drain(&sc->pcie_dll_timer);
+	return (0);
+}
 #endif
 
 /*
@@ -1592,6 +1677,39 @@
 }
 
 int
+pcib_detach(device_t dev)
+{
+#if defined(PCI_HP) || defined(NEW_PCIB)
+	struct pcib_softc *sc;
+#endif
+	int error;
+
+#if defined(PCI_HP) || defined(NEW_PCIB)
+	sc = device_get_softc(dev);
+#endif
+	error = bus_generic_detach(dev);
+	if (error)
+		return (error);
+#ifdef PCI_HP
+	if (sc->flags & PCIB_HOTPLUG) {
+		error = pcib_detach_hotplug(sc);
+		if (error)
+			return (error);
+	}
+#endif
+	error = device_delete_children(dev);
+	if (error)
+		return (error);
+#ifdef NEW_PCIB
+	pcib_free_windows(sc);
+#ifdef PCI_RES_BUS
+	pcib_free_secbus(dev, &sc->bus);
+#endif
+#endif
+	return (0);
+}
+
+int
 pcib_suspend(device_t dev)
 {
 
Index: sys/dev/pci/pcib_private.h
===================================================================
--- sys/dev/pci/pcib_private.h
+++ sys/dev/pci/pcib_private.h
@@ -160,6 +160,7 @@
 struct resource *pcib_alloc_subbus(struct pcib_secbus *bus, device_t child,
 		    int *rid, rman_res_t start, rman_res_t end, rman_res_t count,
 		    u_int flags);
+void		pcib_free_secbus(device_t dev, struct pcib_secbus *bus);
 void		pcib_setup_secbus(device_t dev, struct pcib_secbus *bus,
     int min_count);
 #endif
@@ -171,6 +172,7 @@
 const char	*pcib_child_name(device_t child);
 #endif
 int		pcib_child_present(device_t dev, device_t child);
+int		pcib_detach(device_t dev);
 int		pcib_read_ivar(device_t dev, device_t child, int which, uintptr_t *result);
 int		pcib_write_ivar(device_t dev, device_t child, int which, uintptr_t value);
 struct resource *pcib_alloc_resource(device_t dev, device_t child, int type, int *rid,