dev->transfer = hmcfgusb_prepare_int(devh, hmcfgusb_interrupt, cb_data);
if (!dev->transfer) {
fprintf(stderr, "Can't prepare async device io!\n");
dev->transfer = hmcfgusb_prepare_int(devh, hmcfgusb_interrupt, cb_data);
if (!dev->transfer) {
fprintf(stderr, "Can't prepare async device io!\n");