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List:       linux-ide
Subject:    Re: [PATCH] scsi_lib.c: continue after MEDIUM_ERROR
From:       Mark Lord <liml () rtr ! ca>
Date:       2007-01-31 18:37:56
Message-ID: 45C0E204.3030901 () rtr ! ca
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James Bottomley wrote:
> 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.

My suggestion above was not for a kernel fix,
but rather just as a way of determining if drives
which claim "no retries" actually do them or not.  :)

> 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.

Good.  That would be a useful supplement to the patch I posted here.

Cheers
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