HPET_OPEN
if (hpetp->hp_dev[i].hd_flags & HPET_OPEN) {
devp->hd_flags |= HPET_OPEN;
devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
if ((devp->hd_flags & HPET_OPEN) == 0) {
devp->hd_flags = HPET_OPEN;