Date: Mon, 27 Nov 1995 09:35:04 -0500 (EST) From: Peter Dufault <dufault@hda.com> To: joerg_wunsch@uriah.heep.sax.de Cc: mark@linus.demon.co.uk, julian@ref.tfs.com, freebsd-scsi@freebsd.org Subject: Re: kern/820: scsi tape problems Message-ID: <199511271435.JAA04871@hda.com> In-Reply-To: <199511270904.KAA05088@uriah.heep.sax.de> from "J Wunsch" at Nov 27, 95 10:04:44 am
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> > This allowed to me to successfully read the tape (yes, my tape drive > > really did take >100s to read that block!). > > Peter? Do you remember our discussion about SCSI adaptor timeouts? > > We should bring this up again in freebsd-scsi. I could bury out the > old mails. Host adapter timeouts or transaction timeouts? I have mail on transaction timeouts and on my "TODO someday soon" list, and I don't think it applies in this case - we talked about both retrying "forever" for a "device is in the process of becoming ready" error and to delay a bit (where "a bit" gets longer between each retry) instead of doing an immediate retry - I don't think we talked about something that takes an unexpectedly long amount of time (100s for a read of a tape block) and that we (think we) can't abort. This case was a transaction that timed out, and then we tried to abort it (I'm not sure what the 1542 firmware does when you tell it to abort a transaction - I don't know if it does a BUS DEVICE RESET or what, and I don't have a 1542 manual) and we apparently then decided our host adapter was dead when it couldn't abort that transaction in four seconds. So there are two problems here, one general and one 1542 specific: 1. It would be nice to be able to tune the timeouts on a device by device basis for when you have a device with an unusually long timeout; 2. That "abort transaction" / "host adapter is hosed" branch needs some fixing. -- Peter Dufault Real Time Machine Control and Simulation HD Associates, Inc. Voice: 508 433 6936 dufault@hda.com Fax: 508 433 5267
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