xhci_interrupt_poll
usb_callout_reset(&sc->sc_callout, 1, (void *)&xhci_interrupt_poll, sc);
xhci_interrupt_poll(sc);
if (err != 0 && xhci_interrupt_poll(sc) != 0) {
xhci_interrupt_poll(sc);
xhci_interrupt_poll(sc);
usb_callout_reset(&sc->sc_callout, 1, (void *)&xhci_interrupt_poll, sc);
xhci_interrupt_poll(sc);