if (usbInterruptIsReady()) {
if (kbuf_head != kbuf_tail) {
usbSetInterrupt((void *)&kbuf[kbuf_tail], sizeof(report_keyboard_t));
if (usbInterruptIsReady()) {
if (kbuf_head != kbuf_tail) {
usbSetInterrupt((void *)&kbuf[kbuf_tail], sizeof(report_keyboard_t));