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Message-ID: <4B567971.7000904@gmail.com>
Date: Wed, 20 Jan 2010 12:33:05 +0900
From: Tejun Heo <htejun@...il.com>
To: Bart Hartgers <bart.hartgers@...il.com>
CC: linux-kernel@...r.kernel.org, Jeff Garzik <jgarzik@...ox.com>,
linux-ide@...r.kernel.org
Subject: Re: [patch 1/2] sata_via: Correctly setup PIO/DMA for pata slave
on vt6421.
On 01/17/2010 08:56 AM, Bart Hartgers wrote:
> Before only the timings for master were set. Datasheet can be found
> here: ftp://ftp.vtbridge.org/Docs/Storage/DS_VT6421A_100_CCPL.PDF
> Surprisingly, a slave drive works without this patch. According to the
> datasheet, the controller by default derives the DMA mode from the
> Set Features command issued to a drive. Not sure about the PIO
> timings, though. The real problem is that the timings for the master
> effectively are the ones tuned for the slave. If these support
> different UDMA-settings, there is trouble, especially when the slave
> supports a higher UDMA than the master.
>
> Anyhow, using the same mechanism for both master and slave seems like
> a good idea.
>
> Signed-off-by: Bart Hartgers <bart.hartgers@...il.com>
Acked-by: Tejun Heo <tj@...nel.org>
Thanks.
--
tejun
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