file override to disable fifo on 16550s:
I bought a board with two 16550's, but one of those ports has a mouse
on it. The sio driver always enables the fifo, which is a bad thing
for mice and X. The mouse is jerky and hard to use. The simple thing
is be to treat one of the ports as a non-fifo'ed UART, and I use the
flags option in my config file.
So, my config file has:
device sio0 at isa? port "IO_COM1" tty irq 4 flags 0x2 vector siointr
device sio1 at isa? port "IO_COM2" tty irq 3 vector siointr
(patch deleted)