E1000_TXD_CMD_IFCS
(dsc->td.lower.data & E1000_TXD_CMD_IFCS) == 0) {
txp->lower.data = E1000_TXD_CMD_RPS | E1000_TXD_CMD_EOP | E1000_TXD_CMD_IFCS | size;
uint32_t tctl, txd_lower = E1000_TXD_CMD_IFCS;
first_data_desc->lower.data |= E1000_TXD_CMD_IFCS;
descriptor->lower.data |= E1000_TXD_CMD_IFCS;