From: Doug Ledford <dledford@redhat.com>
To: "Justin T. Gibbs" <gibbs@scsiguy.com>
Cc: Mike Brown <mbrown@emc.com>,
bferjul@emc.com, jkrasner@emc.com, conway_heather@emc.com,
linux-scsi@vger.kernel.org
Subject: Re: [PATCH] Ghost devices being reported with AIC7XXX version 6.2.6
Date: Thu, 31 Oct 2002 15:07:58 -0500 [thread overview]
Message-ID: <20021031200758.GB30047@redhat.com> (raw)
In-Reply-To: <798370000.1036087399@aslan.btc.adaptec.com>
On Thu, Oct 31, 2002 at 11:03:19AM -0700, Justin T. Gibbs wrote:
> > Justin can you change AHC_NUM_LUNS to 32 or suggest an alternative fix?
>
> The aic7xxx driver is not at fault and so should not be changed.
> The aic7xxx driver really does support all 64 luns. In my opinion,
> there are three problems here:
>
> 1) The Symetrix should treat a non-zero LUNTAR bit as an invalid
> selection. This would prevent these higher luns from showing up
> as valid devices.
>
> 2) Linux should never use more than 5 bits of lun for a device that
> reports itself as SCSI-2. If the lun is larger than what will
> fit in 3 bits, byte 1 of the CDB should not be altered even if
> the device is SCSI2.
The whole "support more than 8 luns on SCSI-2 devices" is a hack anyway, I
would be more likely to just remove it instead of changing other things.
> 3) Linux should be using the Report Luns command to determine how
> many luns are on a device and at what locations. This might
> even allow you to never probe more than 8 luns on a SCSI 2
> device unless they support this command. Does the Symetrix support
> it? Going beyond 8 luns on a SCSI2 device is really a hack
> otherwise.
We currently only do report luns on SCSI-3 devices. I didn't think this
was a supported command on SCSI-2, but I hadn't checked the spec
recently...hmmm...nope, not supported in SCSI-2, so using report luns on
SCSI-2 devices is just as much a hack as going above lun 7 on SCSI-2
devices without specific knowledge of transfer interconnect.
> --
> Justin
> -
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--
Doug Ledford <dledford@redhat.com> 919-754-3700 x44233
Red Hat, Inc.
1801 Varsity Dr.
Raleigh, NC 27606
next prev parent reply other threads:[~2002-10-31 20:07 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-10-31 17:03 [PATCH] Ghost devices being reported with AIC7XXX version 6.2.6 Mike Brown
2002-10-31 18:03 ` Justin T. Gibbs
2002-10-31 18:28 ` Matthew Jacob
2002-10-31 19:21 ` Alan Cox
2002-10-31 19:30 ` Matthew Jacob
2002-10-31 20:03 ` Doug Ledford
2002-10-31 20:04 ` Matthew Jacob
2002-10-31 20:17 ` Doug Ledford
2002-10-31 20:27 ` Matthew Jacob
2002-10-31 20:40 ` Matthew Jacob
2002-10-31 20:43 ` Doug Ledford
2002-11-01 13:00 ` Alan Cox
2002-11-01 1:41 ` Patrick Mansfield
2002-10-31 20:07 ` Doug Ledford [this message]
2002-10-31 20:26 ` Matthew Jacob
2002-10-31 20:38 ` Doug Ledford
2002-10-31 20:39 ` Matthew Jacob
2002-10-31 20:40 ` Mike Brown
2002-10-31 20:41 ` Matthew Jacob
2002-10-31 21:00 ` Mike Brown
2002-10-31 21:14 ` James Bottomley
2002-10-31 20:38 ` Mike Brown
2002-10-31 21:25 ` Doug Ledford
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