Subject: Re: READ SCSI cmd seems to fail on SATA optical devices...
From: Mathieu Fluhr <mfluhr@nero.com>
To: Arjan van de Ven <arjan@infradead.org>
Cc: Phillip Susi <psusi@cfl.rr.com>, jgarzik@pobox.com,
       linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org
In-Reply-To: <1163446372.15249.190.camel@laptopd505.fenrus.org>
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	 <1163446372.15249.190.camel@laptopd505.fenrus.org>
Content-Type: text/plain
Organization: Nero AG
Date: Tue, 14 Nov 2006 16:45:25 +0100
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On Mon, 2006-11-13 at 20:32 +0100, Arjan van de Ven wrote:
> On Mon, 2006-11-13 at 19:56 +0100, Mathieu Fluhr wrote:
> > On Mon, 2006-11-13 at 13:49 -0500, Phillip Susi wrote:
> > > Mathieu Fluhr wrote:
> > > > Hello,
> > > > 
> > > > I recently tried to burn some datas on CDs and DVD using a SATA burner
> > > > and the latest 2.6.18.2 kernel... using NeroLINUX. (It is controlling
> > > > the device by sending SCSI commands over the 'sg' driver)
> > > > 
> > > 
> > > Please note that the sg interface is depreciated.  It is now recommended 
> > > that you send the CCBs directly to the normal device, i.e. /dev/hdc.
> > 
> > Of course for native IDE devices, we are using the /dev/hdXX device, but
> > for SATA devices controlled by the libata, this is not possible ;)
> 
> for those there is /dev/scd0 etc...
> (usually nicely symlinked to /dev/cdrom)

Hummm as we are _writing_ to devices, I think that using /dev/sgXX with
SG_IO is better no?

... and the problem is not in accessing the device itself (this is
working like a charm) but understanding why a SCSI READ(10) cmd
sometimes fails as a ATA-padded READ(10) cmd - as discribed in the Annex
A of the MMC-5 spec - ALWAYS works.
-> I would suspect somehow a synchronisation problem somehow in the
translation of SCSI to ATA command...

Another point: When I say that a READ(10) fails, it does NOT mean that
the command execution itself fails. Everything works as if the command
exectution succeeds, but the resulting buffer contains garbage (i.e. not
only 1 or 2 bytes differs)


> 
> 

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