if (!xfer_in->user_data)
libusb_cancel_transfer(xfer_in);
if (!xfer_out->user_data)
libusb_cancel_transfer(xfer_out);
start = g_get_monotonic_time();
while (!xfer_in->user_data || !xfer_out->user_data) {
if (!xfer_in->user_data)
libusb_cancel_transfer(xfer_in);
if (!xfer_out->user_data)
libusb_cancel_transfer(xfer_out);
start = g_get_monotonic_time();
while (!xfer_in->user_data || !xfer_out->user_data) {