u8 cdc_ncm_select_altsetting(struct usb_interface *intf)
{
	struct usb_host_interface *alt;

	/* The MBIM spec defines a NCM compatible default altsetting,
	 * which we may have matched:
	 *
	 *  "Functions that implement both NCM 1.0 and MBIM (an
	 *   “NCM/MBIM function”) according to this recommendation
	 *   shall provide two alternate settings for the
	 *   Communication Interface.  Alternate setting 0, and the
	 *   associated class and endpoint descriptors, shall be
	 *   constructed according to the rules given for the
	 *   Communication Interface in section 5 of [USBNCM10].
	 *   Alternate setting 1, and the associated class and
	 *   endpoint descriptors, shall be constructed according to
	 *   the rules given in section 6 (USB Device Model) of this
	 *   specification."
	 */
	if (intf->num_altsetting < 2)
		return intf->cur_altsetting->desc.bAlternateSetting;

	if (prefer_mbim) {
		alt = usb_altnum_to_altsetting(intf, CDC_NCM_COMM_ALTSETTING_MBIM);
		if (alt && cdc_ncm_comm_intf_is_mbim(alt))
			return CDC_NCM_COMM_ALTSETTING_MBIM;
	}
	return CDC_NCM_COMM_ALTSETTING_NCM;
}

Unknown