PL2303_PORT_TX_STOPPED
if ((plp->pl_port_flags & PL2303_PORT_TX_STOPPED) ||
plp->pl_port_flags |= PL2303_PORT_TX_STOPPED;
if (plp->pl_port_flags & PL2303_PORT_TX_STOPPED) {
plp->pl_port_flags &= ~PL2303_PORT_TX_STOPPED;