ibm thinkpad 600, freeze when serial port accessed ...

[bruno schwander]

anytime I try to access the serial port, the laptop freezes and a reboot
is needed.

dmesg output for sio:

sio0: configured irq 4 not in bitmap of probed irqs 0
sio0 at port 0x3f8-0x3ff irq 4 flags 0x10 on isa0
sio0: type 8250

this is on:
FreeBSD thinkpad 4.8-RELEASE FreeBSD 4.8-RELEASE #2: Tue Aug 19 19:44:37
GMT 2003     bruno at thinkpad:/usr/obj/usr/src/sys/THINKPAD  i386

under windows 98 (also installed on that same machine, in an other
partition) I checked that the serial port is enabled and the infrared
serial port disabled (with the special thinkpad configuration tool) .
Windows hardware shows the serial port as irq 4, port 3f8-3ff but who
knows if that what it really should be. I read in some other port that the
'not in bitmap of probed irq' means the port was not detected correctly.
How should that be configured ? Isn't that serial port part of the support
chip ?

Anybody using successfully their serial port on a thinkpad 600, please let
me know your configuration...  Anybody else with ideas on what to check,
let me know !

Thanks,

bruno