From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeff Garzik <jeff@garzik.org>
Subject: Re: Nvidia cable detection problems (was [PATCH] amd74xx: don't configure
 udma mode higher than BIOS did)
Date: Mon, 05 Feb 2007 16:43:24 -0500
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To: Alan <alan@lxorguk.ukuu.org.uk>
Cc: Tejun Heo <htejun@gmail.com>, Allen Martin <AMartin@nvidia.com>, Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>, linux-ide@vger.kernel.org, linux-kernel <linux-kernel@vger.kernel.org>

Alan wrote:
>>> Well we can certainly do some of that if ACPI is present and active. In
>>> particular since _GTM will give us current modes allowing for hotplug and
>>> post BIOS boot kexec etc it ought to be safe to do Tejun's hack that way.
>>> We could even probe UDMA3+ capable devices by doing _STM to a high mode
>>> and _GTM to determine the cable type 8)
>> Glad to see the problem getting solved.  Now that we know the solution,
>> any volunteers?  :-)
> 
> I am currently putting together an experimental pata_acpi driver to play
> with this stuff. May take a bit of time while I work out the current acpi
> interface gunge and how to expand it.
> 
> The fact we have to try each mode to see what we can set doesn't make it
> pretty either!

Make sure you take a look at libata-dev.git#acpi which is the origin of 
the libata ACPI support found in -mm

That's pending for an upstream merge.

	Jeff