Subject: Re: [PATCH] scsi_lib.c: continue after MEDIUM_ERROR
From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Mark Lord <liml@rtr.ca>
Cc: Alan <alan@lxorguk.ukuu.org.uk>, Ric Wheeler <ric@emc.com>,
       "Eric D. Mudama" <edmudama@gmail.com>, linux-kernel@vger.kernel.org,
       IDE/ATA development list <linux-ide@vger.kernel.org>,
       linux-scsi <linux-scsi@vger.kernel.org>, dougg@torque.net
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Date: Wed, 31 Jan 2007 12:13:18 -0600
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On Wed, 2007-01-31 at 12:57 -0500, Mark Lord wrote:
> Alan wrote:
> >> When libata reports a MEDIUM_ERROR to us, we *know* it's non-recoverable,
> >> as the drive itself has already done internal retries (libata uses the
> >> "with retry" ATA opcodes for this).
> > 
> > This depends on the firmware. Some of the "raid firmware" drives don't
> > appear to do retries in firmware.
> 
> One way to tell if this is true, is simply to time how long
> the failed operation takes.  If the drive truly does not do retries,
> then the media error should be reported more or less instantly
> (assuming drive was already spun up).

Well, the simpler way (and one we have a hope of implementing) is to
examine the ASC/ASCQ codes to see if the error is genuinely unretryable.

I seem to have dropped the ball on this one in that the scsi_error.c
pieces of this patch

http://marc.theaimsgroup.com/?l=linux-scsi&m=116485834119885

I thought I'd applied.  Apparently I didn't, so I'll go back and put
them in.

James


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