usb serial lockup

[Vince]

Hi All,
	I have a bit of a wierd problem, My laptop has no serial ports, as is
the norm these days, so i have a FTDI based usb serial connector which
is very handy and works well. However, what i have found is that freebsd
still detects a serial port anyway

sio0: configured irq 4 not in bitmap of probed irqs 0
sio0: port may not be enabled
sio0 at port 0x3f8-0x3ff irq 4 flags 0x10 on isa0
sio0: type 8250 or not responding
sio1: configured irq 3 not in bitmap of probed irqs 0
sio1: port may not be enabled

and if i'm careless and type tip com1 ( or use minicom on /dev/{ttyd0,
cuad0} as root or as a user I hard lock my laptop, nothing responding
and i have to powercycle it. this is 100% reproducable.

I'm pretty sure this isnt expected behaviour, and it has happened from
6.1 through 6-Stable to my latest update (possibly before but i havent
tested:)
6.2-PRERELEASE #12: Mon Nov  6 15:01:21 GMT 2006

any suggestions as to what i can do about it? (other than watch my
typing, if thats the only answer i can live with it though;)


Vince