Date: Tue, 29 Feb 2000 23:48:28 -0700 From: "Kenneth D. Merry" <ken@kdm.org> To: Mike Smith <msmith@FreeBSD.ORG> Cc: scsi@FreeBSD.ORG Subject: Re: chio trap with not-ready changer Message-ID: <20000229234828.A28504@panzer.kdm.org> In-Reply-To: <200003010640.WAA03924@mass.cdrom.com>; from msmith@FreeBSD.ORG on Tue, Feb 29, 2000 at 10:40:39PM -0800 References: <20000229233615.A28297@panzer.kdm.org> <200003010640.WAA03924@mass.cdrom.com>
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On Tue, Feb 29, 2000 at 22:40:39 -0800, Mike Smith wrote: > > On Tue, Feb 29, 2000 at 22:21:39 -0800, Mike Smith wrote: > > > > Okay, I think I know why the panic is happening at least. I don't > > > > understand why you're getting the unit attention error, though, since we > > > > generally retry unit attention errors unconditionally. > > > > > > > > Try the attached patch and see if it fixes things up. Once you've got the > > > > panic fixed, we can attempt to solve the unit attention problem. > > > > > > Ok, it's not panicking anymore: > > > > > > pass0 at ahc0 bus 0 target 4 lun 0 > > > pass0: <SPECTRA STL-8000 1.94> Removable Changer SCSI-2 device > > > pass0: Serial Number 3 > > > pass0: 3.300MB/s transfers > > > ... > > > (ch0:ahc0:0:4:0): MODE SENSE(06). CDB: 1a 0 1d 0 20 0 > > > (ch0:ahc0:0:4:0): UNIT ATTENTION asc:29,0 > > > (ch0:ahc0:0:4:0): Power on, reset, or bus device reset occurred > > > (ch0:ahc0:0:4:0): fatal error, failed to attach to device > > > (ch0:ahc0:0:4:0): lost device > > > (ch0:ahc0:0:4:0): removing device entry > > > > > > Now what? 8) > > > > Well, I still can't figure out how you're getting a failure from a unit > > attention error. I suppose the next thing to try is to bump the retry > > count. The attached patch is the same as before, but with the retry count > > set to 3 instead of 1. > > Ah. I think I understand this. How long is the delay between retries? > Is there anyway to get a "device becoming ready" status? I'd hazard a > guess that you're going to get the above error repeated until the changer > has finished resetting (may be several minutes). What's confusing me about the problem is that cherror() is called with the SF_RETRY_UA flag. That's supposed to return ERESTART on any errors with a unit attention sense key, regardless of the retry count. So it should keep retrying unit attention errors indefinitely. I say indefinitely, but unit attenion conditions should generally be cleared once they're returned once. But that's evidently not happening in your case, and I don't know why. Anyway, to answer your questions: - there is no delay between retries in this case - there are "device becoming ready" status return values, and we do check for that. Ken -- Kenneth Merry ken@kdm.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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