On Fri, Mar 12, 2004 at 06:18:13PM -0500, Charles M. Hannum wrote:
> 
> I strongly suspect that this problem is in the esp driver.  There's at
> least one report on the net of the same drive working with ahc just
> fine.

Well, in this case the fact that it doesn't work under solaris either
is enouth to my eyes.
Some drives can do tagged queuing for a few tags, but when their command
list is full, they wedge instead of returning the appropriate SCSI message.
I ran into this with a IBM drive while developing esiop (it was fine with
siop), a firmware update fixed it.
On a report I see is with a ahc2940. I don't know enouth about FreeBSD and
the ahc driver, but I suspect the "16/255" here restricts the number of
concurent commands per device. However another report with a "32/255" ahc
talks about command timeouts, which seems related to too much tags.
There is also a report with the old linux ncr53x8xx, but this one won't
send much concurent commands (if it does tagged queuing at all).

-- 
Manuel Bouyer <bouyer@antioche.eu.org>
     NetBSD: 26 ans d'experience feront toujours la difference
--