UHCI_INTR
bus_write_2(res, UHCI_INTR, 0);
UWRITE2(sc, UHCI_INTR, 0);
UWRITE2(sc, UHCI_INTR,
UREAD2(sc, UHCI_INTR),
bus_space_write_2(sc->sc_io_tag, sc->sc_io_hdl, UHCI_INTR, 0);