Symbol: UPF_BUG_THRE
drivers/tty/serial/8250/8250_pci.c
1886
port->port.flags |= UPF_BUG_THRE;
drivers/tty/serial/8250/8250_port.c
2187
if ((!iir_noint1 && iir_noint2) || up->port.flags & UPF_BUG_THRE)