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>
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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
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