xhci: Do not issue device reset when device is not setup

xHCI controllers respond to a Reset Device command when the Slot is in the
Enabled/Disabled state by returning an error.  This is fine on other host
controllers, but the Etron xHCI host controller returns a vendor-specific
error code that the xHCI driver doesn't understand.  The xHCI driver then
gives up on device enumeration.

Instead of issuing a command that will fail, just return.  This fixes the
issue with the xhci driver not working on ASRock P67 Pro/Extreme boards.

This should be backported to stable kernels as far back as 2.6.34.

Signed-off-by: Maarten Lankhorst <m.b.lankhorst@gmail.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@kernel.org

drivers/usb/host/xhci.c

@@ -2467,6 +2467,7 @@ int xhci_discover_or_reset_device(struct usb_hcd *hcd, struct usb_device *udev)
 	struct xhci_command *reset_device_cmd;
 	int timeleft;
 	int last_freed_endpoint;
+	struct xhci_slot_ctx *slot_ctx;
 
 	ret = xhci_check_args(hcd, udev, NULL, 0, false, __func__);
 	if (ret <= 0)
@@ -2499,6 +2500,12 @@ int xhci_discover_or_reset_device(struct usb_hcd *hcd, struct usb_device *udev)
 			return -EINVAL;
 	}
 
+	/* If device is not setup, there is no point in resetting it */
+	slot_ctx = xhci_get_slot_ctx(xhci, virt_dev->out_ctx);
+	if (GET_SLOT_STATE(le32_to_cpu(slot_ctx->dev_state)) ==
+						SLOT_STATE_DISABLED)
+		return 0;
+
 	xhci_dbg(xhci, "Resetting device with slot ID %u\n", slot_id);
 	/* Allocate the command structure that holds the struct completion.
 	 * Assume we're in process context, since the normal device reset