Date: Tue, 28 Aug 2001 16:28:12 -0600 From: "Kenneth D. Merry" <ken@kdm.org> To: =?iso-8859-1?Q?G=E9rard_Roudier?= <groudier@free.fr> Cc: Thomas Quinot <thomas@cuivre.fr.eu.org>, stable@FreeBSD.ORG, scsi@FreeBSD.ORG Subject: Re: Failure to attach SCSI CD burner Message-ID: <20010828162812.A31937@panzer.kdm.org> In-Reply-To: <20010828212323.J1476-100000@gerard>; from groudier@free.fr on Tue, Aug 28, 2001 at 10:00:11PM %2B0200 References: <20010827135440.A21092@panzer.kdm.org> <20010828212323.J1476-100000@gerard>
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On Tue, Aug 28, 2001 at 22:00:11 +0200, Gérard Roudier wrote: > On Mon, 27 Aug 2001, Kenneth D. Merry wrote: > > On Mon, Aug 27, 2001 at 21:35:28 +0200, Gérard Roudier wrote: > > > On Sun, 26 Aug 2001, Kenneth D. Merry wrote: > > > > On Mon, Aug 27, 2001 at 01:09:14 +0200, Thomas Quinot wrote: > > > > > Le 2001-08-26, Kenneth D. Merry écrivait : > > > > > > > > > > > Hmm. Well, try applying the attached patch to sys/cam/scsi/scsi_cd.c and > > > > > > recompile your kernel. > > > > > > > > > > OK, some new info: > > > > > > > > > > 1. with NO CD in the drive, I did not actually get the failure reported > > > > > before, but only the following messages: > > > > > > > > > > cd0 at sym0 bus 0 target 2 lun 0 > > > > > cd0: <IMS CDD2000/00 1.26> Removable CD-ROM SCSI-2 device > > > > > cd0: 3.300MB/s transfers > > > > > cd0: Attempt to query device size failed: NOT READY, Logical unit not ready, cause not reportable > > > > > > > > > > (and then subsequently cd0 was correctly attached and usable) > > > > > > > > That's normal. > > > > > > > > > 2. with a DEFECTIVE CD-R in the drive (that had been sitting in there > > > > > for some time I guess...) I reproduced the failure: > > > > > > > > > > (cd0:sym0:0:2:0): autosense is NOT valid > > > > > (cd0:sym0:0:2:0): flags = 0x40 status = 0x4c > > > > > (cd0:sym0:0:2:0): got CAM status 0x4c > > > > > (cd0:sym0:0:2:0): fatal error, failed to attach to device > > > > > (cd0:sym0:0:2:0): lost device > > > > > (cd0:sym0:0:2:0): removing device entry > > > > > > > > > > and then retrying the command with camcontrol yields /valid/ > > > > > sense data. > > > > > > > > Hmm, okay. So the drive was not empty before when you were having > > > > failures? It looks like, at least the first time through, the autosense > > > > valid flag isn't getting set for the read capacity command. > > > > > > > > Gerard, do you have any ideas as to why the autosense valid bit might not > > > > be getting set the first time we send a read capacity to his drive? > > > > (Apparantly with a certain bad CD-R in the drive.) > > > > > > I could better understand the situation if I got the previous postings on > > > this topic. Btw, I didn't retrieve in what place the first 2 messages are > > > printed from the code. May-be they are just printed out by your patch (?). > > > > They're on the -scsi list, I figured you were still on the list. > > > > See: > > > > http://docs.freebsd.org/mail/archive/2001/freebsd-scsi/20010826.freebsd-scsi.html > > http://docs.freebsd.org/mail/current/freebsd-scsi.html > > > > Yes, the first two lines are printed out by a patch I gave Thomas. (To > > figure out why the cd(4) driver was not attaching. It will attach, > > regardless of the SCSI sense sent back, unless the sense information is > > "logical unit not supported". When there is no sense, though, there's no > > way to figure out what's going on.) > > > > > If I understand your statement, the SIM is reported a CHECK CONDITION SCSI > > > status from the device, but does not assert the CAM_AUTOSNS_VALID flag. Is > > > my guessing correct? > > > > Yes, that is what it looks like is happening. Apparantly it only happens > > the first time we send a read capacity to the drive. (On probe.) > > Subsequent read capacity commands via camcontrol return CCBs with valid > > sense data and the CAM_AUTOSNS_VALID flag set. > > I double-checked the sym driver source and didn't find any code path > explaining such behaviour. I mean, the driver returning SCSI_STATUS_ERROR > on either CHECK CONDITION or TERMINATED STATUS. If an error occurs during > auto-sense, the driver should either return some severe cam status value, > or indicate that sense data are not valid in the cam status. Well, it looks like it's doing just that -- returning CAM_SCSI_STATUS_ERROR, but without the CAM_AUTOSNS_VALID flag set. > It would have been fine to also display out the actual value of the scsi > status returned by the device. Being 100% sure is far better than only > 99%. :) > Let me suggest Thomas to add such a trace to scsi_cd.c and to give another > try with his CD burner. The patch I gave him does this -- the status is 0x4c, which is CAM_SCSI_STATUS_ERROR | CAM_DEV_QFRZN. (See above.) > This 1% of chance for another SCSI status to have been returned gives the > following scenario some chance to happen. :) > > The read capacity is performed with 1 retry max by the cd driver. > > 1) The device returns SCSI_STATUS_BUSY. > 2) 1 second later the retry is performed. > 3) The device still returns SCSI_STATUS_BUSY. > 4) cam_periph_errof() return EIO. > 5) then the problem reported by Thomas does happen. > > I may be wrong, obviously. Sorry if I am. You've got a point, it may well be returning busy instead of check condition. I'll send him another patch to check for that. Ken -- Kenneth Merry ken@kdm.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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