Skip site navigation (1)Skip section navigation (2)
Date:      Fri, 30 Aug 1996 22:48:02 +0200 (MET DST)
From:      Stefan Esser <se@zpr.uni-koeln.de>
To:        "Justin T. Gibbs" <gibbs@freefall.freebsd.org>
Cc:        Stefan Esser <se@zpr.uni-koeln.de>, Brian Wang <brian@vividnet.com>, freebsd-scsi@FreeBSD.ORG
Subject:   Re: NCR0+IBM DORS-32160 WA0A 2 gigs HD - assertion "cp" failed 
Message-ID:  <199608302048.WAA07233@x14.mi.uni-koeln.de>
In-Reply-To: <199608301636.JAA03192@freefall.freebsd.org>
References:  <199608301544.RAA02753@x14.mi.uni-koeln.de> <199608301636.JAA03192@freefall.freebsd.org>

next in thread | previous in thread | raw e-mail | index | archive | help
Justin T. Gibbs writes:
 > >Up to now, I always choose devices that did not 
 > >fail, and it seems that the DORS is finally a drive
 > >that I can expect to show errors on my development
 > >system, giving me a chance to understand why a modern
 > >drive does not work correctly with tags ...
 > >
 > >Regards, STefan
 > 
 > These errors are for the QUEUE FULL condition right?  I think drives
 > are allowed to return this even if the cause is temporary.  We'll have
 > to come up with a strategy for when to reduce maxtags on drives that
 > doesn't penalize drives that do this kind of thing occasionally.

Well, the NCR driver tries to do the right thing
(reduce the number of tags in case of a QUEUE FULL)
but it would never use a higher number again, after
it had to cut down on tags use. But as I said before,
I'm not sure whether the code works as designed.

If you manage to deal with this correctly in your new 
SCSI code, a better implementation might be possible ...

We have the IBM 0662..0664 drives as prime example of 
a drive that might reject tagged commands in certain 
situations, but IIRC, they do not return a QUEUE FULL, 
but a "MIX of tagged and untagged commands" error status.

I will be busy with non-BSD stuff again this weekend, so 
there will be no advances to the NCR driver integration.
(Sorry ...)

Did you consider putting your changes on a CVS branch in 
-current ? This would GREATLY reduce the amount of work 
it takes me to have a development source tree ..

Regards, STefan



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199608302048.WAA07233>