int usb_set_interface(struct usb_device *dev, int interface, int alternate)
{
        struct usb_interface *iface;
        struct usb_host_interface *alt;
        struct usb_hcd *hcd = bus_to_hcd(dev->bus);
        int i, ret, manual = 0;
        unsigned int epaddr;
        unsigned int pipe;

        if (dev->state == USB_STATE_SUSPENDED)
                return -EHOSTUNREACH;

        iface = usb_ifnum_to_if(dev, interface);
        if (!iface) {
                dev_dbg(&dev->dev, "selecting invalid interface %d\n",
                        interface);
                return -EINVAL;
        }
        if (iface->unregistering)
                return -ENODEV;

        alt = usb_altnum_to_altsetting(iface, alternate);
        if (!alt) {
                dev_warn(&dev->dev, "selecting invalid altsetting %d\n",
                         alternate);
                return -EINVAL;
        }

        /* Make sure we have enough bandwidth for this alternate interface.
         * Remove the current alt setting and add the new alt setting.
         */
        mutex_lock(hcd->bandwidth_mutex);
        /* Disable LPM, and re-enable it once the new alt setting is installed,
         * so that the xHCI driver can recalculate the U1/U2 timeouts.
         */
        if (usb_disable_lpm(dev)) {
                dev_err(&iface->dev, "%s Failed to disable LPM\n.", __func__);
                mutex_unlock(hcd->bandwidth_mutex);
                return -ENOMEM;
        }
        /* Changing alt-setting also frees any allocated streams */
        for (i = 0; i < iface->cur_altsetting->desc.bNumEndpoints; i++)
                iface->cur_altsetting->endpoint[i].streams = 0;

        ret = usb_hcd_alloc_bandwidth(dev, NULL, iface->cur_altsetting, alt);
        if (ret < 0) {
                dev_info(&dev->dev, "Not enough bandwidth for altsetting %d\n",
                                alternate);
                usb_enable_lpm(dev);
                mutex_unlock(hcd->bandwidth_mutex);
                return ret;
        }

int usb_hcd_alloc_bandwidth(struct usb_device *udev,
                struct usb_host_config *new_config,
                struct usb_host_interface *cur_alt,
                struct usb_host_interface *new_alt)
{
        int num_intfs, i, j;
        struct usb_host_interface *alt = NULL;
        int ret = 0;
        struct usb_hcd *hcd;
        struct usb_host_endpoint *ep;

        hcd = bus_to_hcd(udev->bus);
        if (!hcd->driver->check_bandwidth)
                return 0;

        /* Configuration is being removed - set configuration 0 */
        if (!new_config && !cur_alt) {
                for (i = 1; i < 16; ++i) {
                        ep = udev->ep_out[i];
                        if (ep)
                                hcd->driver->drop_endpoint(hcd, udev, ep);
                        ep = udev->ep_in[i];
                        if (ep)
                                hcd->driver->drop_endpoint(hcd, udev, ep);
                }
                hcd->driver->check_bandwidth(hcd, udev);
                return 0;
        }

/*
 * Configuration and alternate setting changes must be done in
 * process context, not interrupt context (or so documenation
 * for usb_set_interface() and usb_set_configuration() claim).
 */
if (xhci_endpoint_init(xhci, virt_dev, udev, ep, GFP_NOIO) < 0) {
        dev_dbg(&udev->dev, "%s - could not initialize ep %#x\n",
                        __func__, ep->desc.bEndpointAddress);
        return -ENOMEM;
}

if (xhci->quirks & XHCI_MTK_HOST) {
        ret = xhci_mtk_add_ep_quirk(hcd, udev, ep);
        if (ret < 0) {
                xhci_free_or_cache_endpoint_ring(xhci,
                        virt_dev, ep_index);
                return ret;
        }
}