XHCI_TRB_INTR
XHCI_TRB_TDREM(tdsize) | XHCI_TRB_INTR(0));
xt->xt_trbs[off + i].trb_status = LE_32(XHCI_TRB_INTR(0));
XHCI_TRB_INTR(0));
xt->xt_trbs[0].trb_status = LE_32(XHCI_TRB_LEN(8) | XHCI_TRB_INTR(0));
xt->xt_trbs[xt->xt_ntrbs - 1].trb_status = LE_32(XHCI_TRB_INTR(0));