T1_LS
txd->xd1 = htole32(T1_FS | T1_LS | T1_TCH | (len & T1_TBS_MASK));
txd->xd1 = htole32(T1_FS | T1_LS | (len & T1_TBS_MASK));
txd->xd1 = htole32(T1_FS | T1_LS | (len & T1_FL));
txd->xd1 |= htole32(T1_FS | T1_LS | (len & T1_TBS_MASK));
sc->sc_txdescs[lasttx].t1 |= T1_LS;