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Date: Tue, 3 Sep 2002 01:35:25 -0600
From: Erik Andersen <andersen@codepoet.org>
To: Jonathan Woithe <jwoithe@physics.adelaide.edu.au>
Cc: linux-kernel@vger.kernel.org, axboe@suse.de, andre@linux-ide.org
Subject: Re: Linux 2.4.18: short dd read from IDE cdrom
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On Tue Sep 03, 2002 at 04:49:12PM +0930, Jonathan Woithe wrote:
> Hi all
> 
> Yesterday I reported a problem to lkml I observed with `dd' and ide cds:
> > For a number of years now I have duplicated cds using
> >   dd if=/dev/cdrom of=foo.iso
> >   cdrecord ... foo.iso
> > :
> > Today I tried the same trick under 2.4.18 and struck a problem: the kernel
> > would not read the complete CD image. ...
> 
> After further testing, it seems that turning off dma using "hdparm -d 0
> /dev/hdc" allows things to work as expected - the full disk can be read and
> the resulting image is intact.  It appears therefore that the problem may

Interesting.  When DMA is enabled does running 
    blockdev --setra 0 /dev/cdrom
make any difference?

 -Erik

--
Erik B. Andersen             http://codepoet-consulting.com/
--This message was written using 73% post-consumer electrons--
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