Date: Sun, 25 Jan 2009 15:22:11 +0000
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>,
       Mikael Pettersson <mikpe@it.uu.se>, Hugh Dickins <hugh@veritas.com>,
       Jeff Garzik <jgarzik@redhat.com>, "Rafael J. Wysocki" <rjw@sisk.pl>,
       linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: 2.6.29-rc libata sff 32bit PIO regression
Message-ID: <20090125152211.18a838f9@lxorguk.ukuu.org.uk>
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	<20090121214746.2b15d1de@lxorguk.ukuu.org.uk>
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> >> "Note: only 32-bit writes to the data port are allowed when this bit is
> >> set."
> >>   
> >  
> >   Now tell me who forces you to set that bit (I assume it's the write 
> > buffer enable) for the ATAPI devices?
> 
>    Yes, it's the write buffer enable (about which I have written already).

Yeah that seems the best way to go - not I note that the old drivers/ide
driver programs it right for 16bit I/O or doing mixed 16/32 ..

Patch added to my tree which together with Hugh's change should do the
trick. The others I've checked seem to have no such rule except in VLB
space. Never tried ATAPI in anger on a VLB box but it's easy enough to
address and I'll do a third patch for those.

Alan
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