serial is getting pretty hard to use. lots
of low-end motherboards otherwise perfect
for plan 9, either don't have serial ports or
have the irq mappings screwed up in the mp
table. i'm batting 1.000 at home with terminal/
cpu server mb with screwed-up serial.
all the machines i want to have serial consoles
have two serial ports that work great. :-\

also, many of the cards supported by plan 9
are very expensive if you don't need 32 serial
ports in a system and they don't support pcie.

after a crash that scrolled right off the cga,
i finally broke down and took a chance on
the StarTech 4 port pci-e 16c950 card.
(p/n pex4s950) from newegg
complete with octopus cable for $100.

other than the fact that the cable and card
need to be mashed together with excessive
force, it works great. (i did need to remove
the card from the case to apply enough
pressure to make them.) the crystal speed
is 1843200hz.

patch uartpex4s950 is on sources.

- erik