- err = libusb_interrupt_transfer(usbdev->usb_devh, EP_OUT, NULL, 0, &cnt, USB_TIMEOUT);
- if (err) {
- fprintf(stderr, "Can't send data: %s\n", usb_strerror(err));
+ memset(out, 0, sizeof(out));
+
+ err = libusb_interrupt_transfer(usbdev->usb_devh, EP_OUT, out, 0, &cnt, USB_TIMEOUT);
+ if (err && (!silent)) {
+ fprintf(stderr, "Can't send null frame: %s\n", usb_strerror(err));