Subject: Re: READ SCSI cmd seems to fail on SATA optical devices...
From: Arjan van de Ven <arjan@infradead.org>
To: Phillip Susi <psusi@cfl.rr.com>
Cc: Tejun Heo <htejun@gmail.com>, Mathieu Fluhr <mfluhr@nero.com>,
       jgarzik@pobox.com, linux-ide@vger.kernel.org,
       linux-kernel@vger.kernel.org
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Organization: Intel International BV
Date: Wed, 15 Nov 2006 17:20:52 +0100
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On Wed, 2006-11-15 at 11:17 -0500, Phillip Susi wrote:
> Tejun Heo wrote:
> >> The patch _seems_ to solve my problem. I am just really astonished when
> >> I read the diff file :D. Can I expect that it will be merged to the
> >> official kernel sources ?
> > 
> > It seems that some devices choke when the bytes after CDB contain 
> > garbage.  I seem to recall that I read somewhere ATAPI device require 
> > left command bytes cleared to zero but I can't find it anywhere now. 
> > Maybe I'm just imagining.  Anyways, yeah, I'll push it to upstream.
> > 
> 
> The original patch memsets the entire buffer only to copy over most of 
> it right after.  Could you amend the patch so that it memcpys first, 
> then memsets only the remainder of the buffer?  No sense wasting cpu 
> cycles.

due to the funnies of how cpu caches work it might not actually be
faster though... Write Allocate and things like that are.. well fun.


-- 
if you want to mail me at work (you don't), use arjan (at) linux.intel.com
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