UCDC_NOTIFICATION_LENGTH
while (actlen - off >= UCDC_NOTIFICATION_LENGTH) {
usbd_copy_out(pc, off, &ucn, UCDC_NOTIFICATION_LENGTH);
UCDC_NOTIFICATION_LENGTH,
off += UCDC_NOTIFICATION_LENGTH + UGETW(ucn.wLength);
if (total_len < UCDC_NOTIFICATION_LENGTH) {
total_len, UCDC_NOTIFICATION_LENGTH);
if (actlen < UCDC_NOTIFICATION_LENGTH) {