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To: asami@cs.berkeley.edu (Satoshi Asami)
cc: gibbs@freebsd.org, scsi@freebsd.org
Subject: Re: NOT READY 
In-reply-to: Your message of "Sun, 27 Jul 1997 14:37:51 PDT."
             <199707272137.OAA02054@blimp.mimi.com> 
Date: Wed, 30 Jul 1997 12:27:04 -0600
From: "Justin T. Gibbs" <gibbs@plutotech.com>
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>sd41(ahc2:9:0): NOT READY asc:4,2
>sd41(ahc2:9:0):  Logical unit not ready, initializing command required
>, retries:3
>===

The drive has spun down and wants you to send it a start unit before
it will play nice again.  The current SCSI code doesn't snoop this
asc,ascq pair and attempt to start the drive up again which is the
problem with the recovery attempt.  I twould not be easy for me
to do anythine at the aic7xxx driver level to address this cleanly
unless you can provide a trace that shows what the aic7xxx driver might
be doing to cause the drive to spin down.  You could try adding in a start
unit in the sense handler for the sd driver and see if it clears up your
problem.

>Also, it seems odd to me that a warm boot (i.e., no power cycling of
>disks) seems to always clear the problem, at least for the time being.
>Do you think issuing a SCSI bus reset may help?  (I think the old ahc
>driver did this, right?)

The sd driver will perform a start unit (unconditionally) when the
device is opened.  This will cause the drive to spin up and everything
will go back to normal.

>Another odd thing is that 3 out of the 8 are in the same position
>(ahc0:2:0).  I'm not sure if this means the enclosures are to blame.
>(Those are on the third position (out of 7) from the left on the top
>enclosure...not at the edge or anything....)  There are a couple of
>"repeat offenders", but other than those, the problem seems to
>completely go away after rebooting.

It wouldn't surprise me at all if this were a thermal problem.
Stick a temperature sensor in the enclosure (on the drive itself)
and rule this out.

>Satoshi

--
Justin T. Gibbs
===========================================
  FreeBSD: Turning PCs into workstations
===========================================