USB: Fix connected device switch to Inactive state.

[This is upstream commit d3b9d7a.
It needs to be backported to kernels as old as 3.2, because it fixes the
buggy commit 9dbcaec "USB: Handle warm
reset failure on empty port."]

A USB 3.0 device can transition to the Inactive state if a U1 or U2 exit
transition fails.  The current code in hub_events simply issues a warm
reset, but does not call any pre-reset or post-reset driver methods (or
unbind/rebind drivers without them).  Therefore the drivers won't know
their device has just been reset.

hub_events should instead call usb_reset_device.  This means
hub_port_reset now needs to figure out whether it should issue a warm
reset or a hot reset.

Remove the FIXME note about needing disconnect() for a NOTATTACHED
device.  This patch fixes that.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/core/hub.c

@@ -2274,7 +2274,6 @@ static void hub_port_finish_reset(struct usb_hub *hub, int port1,
 	case -ENODEV:
 		clear_port_feature(hub->hdev,
 				port1, USB_PORT_FEAT_C_RESET);
-		/* FIXME need disconnect() for NOTATTACHED device */
 		if (hub_is_superspeed(hub->hdev)) {
 			clear_port_feature(hub->hdev, port1,
 					USB_PORT_FEAT_C_BH_PORT_RESET);
@@ -2308,6 +2307,18 @@ static int hub_port_reset(struct usb_hub *hub, int port1,
 		 * Some companion controllers don't like it when they mix.
 		 */
 		down_read(&ehci_cf_port_reset_rwsem);
+	} else if (!warm) {
+		/*
+		 * If the caller hasn't explicitly requested a warm reset,
+		 * double check and see if one is needed.
+		 */
+		status = hub_port_status(hub, port1,
+					&portstatus, &portchange);
+		if (status < 0)
+			goto done;
+
+		if (hub_port_warm_reset_required(hub, portstatus))
+			warm = true;
 	}
 
 	/* Reset the port */
@@ -3866,12 +3877,21 @@ static void hub_events(void)
 			 */
 			if (hub_port_warm_reset_required(hub, portstatus)) {
 				int status;
+				struct usb_device *udev =
+					hub->hdev->children[i - 1];
 
 				dev_dbg(hub_dev, "warm reset port %d\n", i);
-				status = hub_port_reset(hub, i, NULL,
-						HUB_BH_RESET_TIME, true);
-				if (status < 0)
-					hub_port_disable(hub, i, 1);
+				if (!udev) {
+					status = hub_port_reset(hub, i,
+							NULL, HUB_BH_RESET_TIME,
+							true);
+					if (status < 0)
+						hub_port_disable(hub, i, 1);
+				} else {
+					usb_lock_device(udev);
+					status = usb_reset_device(udev);
+					usb_unlock_device(udev);
+				}
 				connect_change = 0;
 			}