Message-ID: <4D625238.6040503@mvista.com>
Date: Mon, 21 Feb 2011 14:53:28 +0300
From: Sergei Shtylyov <sshtylyov@mvista.com>
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To: Alan Cox <alan@lxorguk.ukuu.org.uk>
CC: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>, linux-ide@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 02/20] ata_piix: unify code for programming PIO and MWDMA
 timings
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Hello.

On 21-02-2011 14:38, Sergei Shtylyov wrote:

>>> PIO mode is setup by different code, and it takes care of the IORDY
>>> setting according to the PIO rules (and it gets called). DMA mode setup should
>>> just ignore the IORDY setting as in all other sane drivers.

>> Well it can't ignore it - but if you mean just keep the bit as is then

> Yes, I mean this.

>> that sounds sensible, have to see what the docs say happens if you ever
>> set MWDMA without IORDY.

> Don't think they say anything on this matter but I can't imagine that IORDY
> matters for DMA.

    What it says is that IORDY enable bit has no effect when the fast timing 
bit is cleared. That's from ICH IDE PRM (29860004.pdf).

WBR, Sergei
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