static void tx_complete(struct usb_ep *ep, struct usb_request *req)
{
	struct printer_dev	*dev = ep->driver_data;

	switch (req->status) {
	default:
		VDBG(dev, "tx err %d\n", req->status);
		fallthrough;
	case -ECONNRESET:		/* unlink */
	case -ESHUTDOWN:		/* disconnect etc */
		break;
	case 0:
		break;
	}

	spin_lock(&dev->lock);
	/* Take the request struct off the active list and put it on the
	 * free list.
	 */
	list_del_init(&req->list);
	list_add(&req->list, &dev->tx_reqs);
	wake_up_interruptible(&dev->tx_wait);
	if (likely(list_empty(&dev->tx_reqs_active)))
		wake_up_interruptible(&dev->tx_flush_wait);

	spin_unlock(&dev->lock);
}
static void tx_complete(struct usb_ep *ep, struct usb_request *req)
{
	struct printer_dev	*dev = ep->driver_data;

	switch (req->status) {
	default:
		VDBG(dev, "tx err %d\n", req->status);
		fallthrough;
	case -ECONNRESET:		 
	case -ESHUTDOWN:		 
		break;
	case 0:
		break;
	}

	spin_lock(&dev->lock);
	 
	list_del_init(&req->list);
	list_add(&req->list, &dev->tx_reqs);
	wake_up_interruptible(&dev->tx_wait);
	if (likely(list_empty(&dev->tx_reqs_active)))
		wake_up_interruptible(&dev->tx_flush_wait);

	spin_unlock(&dev->lock);
}