how to limit SCSI TCQ depth in FreeBSD?

[Don Bowman]

From: Frantisek Rysanek [mailto:Frantisek.Rysanek at post.cz]
> Dear SCSI experts and FreeBSD veterans,
> 
> I'm looking for advice with an apparently simple SCSI issue:
> how do I set a maximum TCQ depth in FreeBSD?
> 
> Scenario:
> - an U320 SCSI disk drive
> - Adaptec 39320 (aic7902) == U320 & PCI-X
> - FreeBSD 5.2.1 (and Linux 2.4.26, for comparison)
> - Bonnie (-s 1500, 4x in parallel, to trash the RAM buffers)
> - the system is a dual Xeon @ 2.6 GHz, 1 GB DDR266,
>    ServerWorks GC-LE (PCI-X)
> 

 ... drive timing out with high tag depth ...
http://lists.freebsd.org/pipermail/freebsd-scsi/2003-August/000443.html
shows a patch i did last year that achieves this.

If you update the firmware on your drive you may find
the problem is resolved as well. I cannot supply the 
firmware, but i can forward you a programming utility
that may upgrade it for you.

--don