Quoting George Harvey <fr30@dial.pipex.com>:

> Hi,
>
> I'm trying to install 3.1 on a Challenge S (IP2x) but unfortunately the
> SCSI probe fails when talking to my IBM DNES-309170 disk. I'm aware that
> this is a known problem with some drives and that it has recently been
> fixed (Ben Harris's message on this list on 24th Sept.). I guess the
> fixes came too late for 3.1 but would it be possible for me to back-port
> them into a custom kernel for my system, and if so, which files do I
> need? I have successfully installed 3.1 on an O2 so can use that to
> build a kernel for my Challenge S.

It would probably be easier to just build a -current kernel and  
install it on the 3.1 system.

If you want to backport it, however, to start you'll need the  
sys/dev/ic/wd33c93* files, which were moved and renamed from the  
original sys/arch/sgimips/hpc/sbic*. I think that the changes are all  
fairly well self-contained, but I don't know what else may have  
changed between 3.x and -current that could complicate things. I also  
seem to recall that Ben touched a few files in sys/dev/scsipi, which  
may be necessary as well.

At the very least, I'd recommend booting a -current kernel just to be  
sure that the wd33c93 changes actually allow your drive to be properly  
detected.

Good luck,
Steve