[PATCH v4 5/5] usb: xhci: Handle USB transaction error on address command

[Lu Baolu <baolu.lu@linux.intel.com>]

Xhci driver handles USB transaction errors on transfer events,
but transaction errors are possible on address device command
completion events as well.

The xHCI specification (section 4.6.5) says: A USB Transaction
Error Completion Code for an Address Device Command may be due
to a Stall response from a device. Software should issue a Disable
Slot Command for the Device Slot then an Enable Slot Command to
recover from this error.

This patch handles USB transaction errors on address command
completion events. The related discussion threads can be found
through below links.

http://marc.info/?l=linux-usb&m=149362010728921&w=2
http://marc.info/?l=linux-usb&m=149252752825755&w=2

Suggested-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/usb/host/xhci.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index d6b728d..c8a64d2 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3822,6 +3822,13 @@ static int xhci_setup_device(struct usb_hcd *hcd, struct usb_device *udev,
 		break;
 	case COMP_USB_TRANSACTION_ERROR:
 		dev_warn(&udev->dev, "Device not responding to setup %s.\n", act);
+
+		mutex_unlock(&xhci->mutex);
+		ret = xhci_disable_slot(xhci, udev->slot_id);
+		if (!ret)
+			xhci_alloc_dev(hcd, udev);
+		mutex_lock(&xhci->mutex);
+
 		ret = -EPROTO;
 		break;
 	case COMP_INCOMPATIBLE_DEVICE_ERROR:
-- 
2.7.4