UHCI_PTR_VF
p->td.td_link = htole32(lastlink | UHCI_PTR_VF | UHCI_PTR_TD);
dataend->td.td_link = htole32(stat->physaddr | UHCI_PTR_VF | UHCI_PTR_TD);
setup->td.td_link = htole32(next->physaddr | UHCI_PTR_VF | UHCI_PTR_TD);