IXGBE_MFLCN_RFCE
mflcn_reg &= ~(IXGBE_MFLCN_RPFCE_MASK | IXGBE_MFLCN_RFCE);
mflcn_reg |= IXGBE_MFLCN_RFCE;
mflcn_reg |= IXGBE_MFLCN_RFCE;
reg &= ~(IXGBE_MFLCN_RPFCE_MASK | IXGBE_MFLCN_RFCE);
flow_rx = !!(mflcn & IXGBE_MFLCN_RFCE);