Index: usb.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/usb.c,v
retrieving revision 1.35
diff -u -p -r1.35 usb.c
--- usb.c	1 Nov 2006 03:37:24 -0000	1.35
+++ usb.c	11 Mar 2007 08:27:37 -0000
@@ -119,7 +119,8 @@ const struct cdevsw usb_cdevsw = {
 };
 #endif
 
-Static volatile int threads_pending = 0;
+Static volatile int usb1_threads_pending = 0;
+Static volatile int usb2_threads_pending = 0;
 
 Static void	usb_discover(void *);
 Static void	usb_create_event_thread(void *);
@@ -249,7 +250,9 @@ usb_create_event_thread(void *arg)
 	static int created = 0;
 
 	if (sc->sc_bus->usbrev == USBREV_2_0)
-		threads_pending++;
+		usb2_threads_pending++;
+	else
+		usb1_threads_pending++;
 
 	if (kthread_create(usb_event_thread, sc, &sc->sc_event_thread,
 	    "%s", sc->sc_dev.dv_xname))
@@ -307,9 +310,22 @@ usb_event_thread(void *arg)
 
 	DPRINTF(("usb_event_thread: start\n"));
 
+	/* USB2 threads wait for USB1 threads to finish their power on. */
+	while (sc->sc_bus->usbrev == USBREV_2_0 && usb1_threads_pending)
+		(void)tsleep((void *)&usb1_threads_pending, PWAIT, "pwron", 0);
+
+	/* Power on ports. */
+	sc->sc_bus->root_hub->hub->poweron(sc->sc_bus->root_hub);
+
+	/* Wake up any USB2 threads waiting for their companions to poweron. */
+	if (sc->sc_bus->usbrev != USBREV_2_0) {
+		usb1_threads_pending--;
+		wakeup((void *)&usb1_threads_pending);
+	}
+
 	/* USB1 threads wait for USB2 threads to finish their first probe. */
-	while (sc->sc_bus->usbrev != USBREV_2_0 && threads_pending)
-		(void)tsleep((void *)&threads_pending, PWAIT, "config", 0);
+	while (sc->sc_bus->usbrev != USBREV_2_0 && usb2_threads_pending)
+		(void)tsleep((void *)&usb2_threads_pending, PWAIT, "config", 0);
 
 	/* Make sure first discover does something. */
 	sc->sc_bus->needs_explore = 1;
@@ -318,8 +334,8 @@ usb_event_thread(void *arg)
 
 	/* Wake up any companions waiting for handover before their probes. */
 	if (sc->sc_bus->usbrev == USBREV_2_0) {
-		threads_pending--;
-		wakeup((void *)&threads_pending);
+		usb2_threads_pending--;
+		wakeup((void *)&usb2_threads_pending);
 	}
 
 	while (!sc->sc_dying) {
Index: usbdivar.h
===================================================================
RCS file: /cvs/src/sys/dev/usb/usbdivar.h,v
retrieving revision 1.24
diff -u -p -r1.24 usbdivar.h
--- usbdivar.h	31 May 2006 06:18:09 -0000	1.24
+++ usbdivar.h	11 Mar 2007 08:27:37 -0000
@@ -92,6 +92,7 @@ struct usbd_port {
 };
 
 struct usbd_hub {
+	usbd_status	      (*poweron)(usbd_device_handle hub);
 	usbd_status	      (*explore)(usbd_device_handle hub);
 	void		       *hubsoftc;
 	usb_hub_descriptor_t	hubdesc;
Index: uhub.c
===================================================================
RCS file: /cvs/src/sys/dev/usb/uhub.c,v
retrieving revision 1.34
diff -u -p -r1.34 uhub.c
--- uhub.c	26 Jun 2006 19:12:38 -0000	1.34
+++ uhub.c	11 Mar 2007 08:27:38 -0000
@@ -85,6 +85,7 @@ struct uhub_softc {
 #define UHUB_IS_HIGH_SPEED(sc) (UHUB_PROTO(sc) != UDPROTO_FSHUB)
 #define UHUB_IS_SINGLE_TT(sc) (UHUB_PROTO(sc) == UDPROTO_HSHUBSTT)
 
+Static usbd_status uhub_poweron(usbd_device_handle hub);
 Static usbd_status uhub_explore(usbd_device_handle hub);
 Static void uhub_intr(usbd_xfer_handle, usbd_private_handle,usbd_status);
 
@@ -158,7 +159,7 @@ USB_ATTACH(uhub)
 	struct usbd_hub *hub = NULL;
 	usb_device_request_t req;
 	usb_hub_descriptor_t hubdesc;
-	int p, port, nports, nremov, pwrdly;
+	int p, port, nports, nremov;
 	usbd_interface_handle iface;
 	usb_endpoint_descriptor_t *ed;
 	struct usbd_tt *tts = NULL;
@@ -282,9 +283,10 @@ USB_ATTACH(uhub)
 	 * These are the events on the bus when a hub is attached:
 	 *  Get device and config descriptors (see attach code)
 	 *  Get hub descriptor (see above)
+	 * (below happens in poweron code, and is deferred for the root hub)
 	 *  For all ports
 	 *     turn on power
-	 *     wait for power to become stable
+	 *  Wait for power to become stable
 	 * (all below happens in explore code)
 	 *  For all ports
 	 *     clear C_PORT_CONNECTION
@@ -326,21 +328,11 @@ USB_ATTACH(uhub)
 		}
 	}
 
-	/* XXX should check for none, individual, or ganged power? */
-
-	pwrdly = dev->hub->hubdesc.bPwrOn2PwrGood * UHD_PWRON_FACTOR
-	    + USB_EXTRA_POWER_UP_TIME;
-	for (port = 1; port <= nports; port++) {
-		/* Turn the power on. */
-		err = usbd_set_port_feature(dev, port, UHF_PORT_POWER);
-		if (err)
-			printf("%s: port %d power on failed, %s\n",
-			       USBDEVNAME(sc->sc_dev), port,
-			       usbd_errstr(err));
-		DPRINTF(("usb_init_port: turn on port %d power\n", port));
-		/* Wait for stable power. */
-		usbd_delay_ms(dev, pwrdly);
-	}
+	/* Defer power on for the root hub until all controllers are ready. */
+	if (dev->powersrc->parent == NULL)
+		hub->poweron = uhub_poweron;
+	else
+		uhub_poweron(dev);
 
 	/* The usual exploration will finish the setup. */
 
@@ -353,6 +345,38 @@ USB_ATTACH(uhub)
 		free(hub, M_USBDEV);
 	dev->hub = NULL;
 	USB_ATTACH_ERROR_RETURN;
+}
+
+usbd_status
+uhub_poweron(usbd_device_handle dev)
+{
+	usb_hub_descriptor_t *hd = &dev->hub->hubdesc;
+	struct uhub_softc *sc = dev->hub->hubsoftc;
+	usbd_status err;
+	int port;
+
+	DPRINTFN(1,("uhub_poweron dev=%p\n", dev));
+
+	/* Ignore hubs that are too deep. */
+	if (dev->depth > USB_HUB_MAX_DEPTH)
+		return (USBD_TOO_DEEP);
+
+	/* Turn the power on for all ports. */
+	for (port = 1; port <= hd->bNbrPorts; port++) {
+		DPRINTF(("uhub_poweron_reset: turn on hub %s port %d power\n",
+		    USBDEVNAME(sc->sc_dev), port));
+		err = usbd_set_port_feature(dev, port, UHF_PORT_POWER);
+		if (err)
+			printf("%s: port %d power on failed, %s\n",
+			       USBDEVNAME(sc->sc_dev), port,
+			       usbd_errstr(err));
+	}
+
+	/* Wait for stable power. */
+	usbd_delay_ms(dev, hd->bPwrOn2PwrGood * UHD_PWRON_FACTOR
+	    + USB_EXTRA_POWER_UP_TIME);
+
+	return (USBD_NORMAL_COMPLETION);
 }
 
 usbd_status