Re: sym53c875: reading /proc causes SCSI parity error - Mathieu Chouquet-Stringer

From: Mathieu Chouquet-Stringer <mathieu@newview.com>
To: haferfrost@web.de ("Matthias Benkmann")
Cc: linux-kernel@vger.kernel.org
Subject: Re: sym53c875: reading /proc causes SCSI parity error
Date: 28 Nov 2001 14:56:13 -0500	[thread overview]
Message-ID: <xlt8zcqsm8y.fsf@shookay.e-steel.com> (raw)
In-Reply-To: <3C053AF2.10037.4CCE47@localhost> <3C054BA2.9822.8DFF90@localhost>
In-Reply-To: <3C054BA2.9822.8DFF90@localhost>

Ok I found the mail in some archives: it does not happen with
/proc/scsi/sym... but with /proc/bus/pci/xx (it seems that it messes the
scsi chip).

Here the answer (note that as a regular user you can't read more than the
first 128 bytes):
http://groups.google.com/groups?hl=en&threadm=fa.fhj0sbv.1ans7qt%40ifi.uio.no&rnum=1&prev=/groups%3Fq%3Dsym53c8xx%2Bproc%2Bscsi%2Breset%2Blinux%2Bmathieu%26hl%3Den%26rnum%3D1%26selm%3Dfa.fhj0sbv.1ans7qt%2540ifi.uio.no

> Oh, I've forgotten another thing. If I do cat /proc/bus/pci/00/* when I'm
> root (and only root), I get scsi reset (especially when I'm copying big
> files). Is this a bug or a feature?

Both. :-)
You donnot want to read configuration space beyong byte 128 for chip
earlier than SYM53C896.

Regards,
   Gérard.

haferfrost@web.de ("Matthias Benkmann") writes:
> On 28 Nov 2001, at 14:13, Mathieu Chouquet-Stringer wrote:
> 
> > I bet it only happens when you're root and you read =
> /proc/scsi/sym53c8xx/0
> > (or whatever in your case).
> >=20
> > I had this discussion with G=E9rard Roudier and it's not a bug, =
> rather a
> > feature...
> 
> Care to elaborate? What happens when you read that file? And why does =
> it=20
> cause an error even when the disk is not currently being accessed? As I =
> 
> said there can be considerable time between running my script and=20
> accessing the disk. And why do I get different errors depending on =
> whether=20
> I access the disk before I run the script or run the script before I=20
> access the disk?
> 
> MSB
> 
> ----
> Who is this General Failure,
> and why is he reading my disk ?
> 
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-- 
Mathieu Chouquet-Stringer              E-Mail : mathieu@newview.com
    It is exactly because a man cannot do a thing that he is a
                      proper judge of it.
                      -- Oscar Wilde