struct urb *urbIn;      /* BULK-transfer handling: urb */
        int8_t *transfer_buffer;
        int16_t *insnBuffer;    /* input buffer for single insn */
-       int ifnum;              /* interface number */
        struct usb_interface *intf;     /* interface structure */
        /* comedi device for the interrupt context */
        struct comedi_device *comedidev;
        devpriv->comedidev = dev;
        devpriv->usb = usb;
        devpriv->intf = intf;
-       devpriv->ifnum = intf->altsetting->desc.bInterfaceNumber;
        usb_set_intfdata(intf, devpriv);
 
        devpriv->dux_commands = kmalloc(SIZEOFDUXBUFFER, GFP_KERNEL);
        if (!devpriv->insnBuffer)
                return -ENOMEM;
 
-       ret = usb_set_interface(devpriv->usb, devpriv->ifnum, 1);
+       ret = usb_set_interface(devpriv->usb,
+                               intf->altsetting->desc.bInterfaceNumber, 1);
        if (ret < 0) {
                dev_err(&intf->dev,
                        "could not switch to alternate setting 1\n");