FW: [PATCH] usb: xhci: lack of clearing xHC resources

[Pawel Laszczak <pawell@cadence.com>]

The xHC resources allocated for USB devices are not released in correct
order after resuming in case when while suspend device was reconnected.

This issue has been detected during the fallowing scenario:
- connect hub HS to root port
- connect LS/FS device to hub port
- wait for enumeration to finish
- force DUT to suspend
- reconnect hub attached to root port
- wake DUT

For this scenario during enumeration of USB LS/FS device the Cadence xHC
reports completion error code for xHCi commands because the devices was not
property disconnected and in result the xHC resources has not been
correct freed.
XHCI specification doesn't mention that device can be reset in any order
so, we should not treat this issue as Cadence xHC controller bug.
Similar as during disconnecting in this case the device should be cleared
starting form the last usb device in tree toward the root hub.
To fix this issue usbcore driver should disconnect all USB
devices connected to hub which was reconnected while suspending.

Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
cc: <stable@vger.kernel.org>
Signed-off-by: Pawel Laszczak <pawell@cadence.com>
---
 drivers/usb/core/hub.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 0cd44f1fd56d..2473cbf317a8 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3627,10 +3627,12 @@ static int finish_port_resume(struct usb_device *udev)
 		 * the device will be rediscovered.
 		 */
  retry_reset_resume:
-		if (udev->quirks & USB_QUIRK_RESET)
+		if (udev->quirks & USB_QUIRK_RESET) {
 			status = -ENODEV;
-		else
+		} else {
+			hub_disconnect_children(udev);
 			status = usb_reset_and_verify_device(udev);
+		}
 	}
 
 	/* 10.5.4.5 says be sure devices in the tree are still there.
-- 
2.43.0