This page exists simply to provide a few keywords to hopefully help people find the odd clue for a technical hitch that didn't turn up a lot of hits in the search engines when I was struggling with it.
A few such issues are collected here: CLUESTICK


FreeBSD irq conflict symptoms, s3 & modem


As a FreeBSD newbie using the 4.7-RELEASE, I tried to install an internal modem on com3, irq5 of my FreeBSD box and took a while to realize that it was an irq conflict that was causing problems. When I ran "dmesg | grep sio" to see boot messages regarding my serial ports, the message for sio2 indicated something about the irq not appearing in the probe bitmap (I've forgotten the exact message). This should have alerted me straight away that it was a straightforward irq clash, but when searching the web for info on 'freebsd, probe, irq & bitmap' I was unable to find anything to indicate that this message was anything to worry about. For some strange reason I foolishly assumed it was simply a warning message that could be ignored. They really should make those messages scarier!
I then spent a lot of time wondering why I could apparently connect to the modem using cu -
e.g "cu -l /dev/cuaa2"
..but when I entered various AT commands such as ATZ, I got no response.
The conflict was with an S3 video card, so fiddling with the irq pci mappings in the BIOS fixed it.

The reason for playing with the at commands in the first place was to see if my modem was fax capable, so I could use it with the hylafax software - www.hylafax.org.

They gave this example:
hyla% cu -l ttyf2
Connected
at+fclass=?
0,1,2
OK
~[hyla].
Disconnected

When I tried this, I got the characters of the at command I entered echoed one behind (e.g the 'a' didn't show until I hit the 't', the 't' displayed when I hit the '+' etc etc in at+fclass=?) There was no 0,1,2 OK response.
Seeing as I was unfamiliar with the strange effects an irq conflict might have - I was simply left wondering whether my modem simply didn't support these AT commands, or if I was doing something else wrong. Nowhere in my web searches could I find a reason why my AT commands weren't giving a response. So.. hence this rambling page of newbie frustration which one day may actually help someone.. or might just add to the general net noise of useless crap.


ju li-an at vector-stream dot com
(remove the dashes to email)

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