From mboxrd@z Thu Jan  1 00:00:00 1970
From: "George Spelvin" <linux@horizon.com>
Subject: Re: What's the SB600 64-bit DMA problem?
Date: Sun, 28 Sep 2008 17:04:22 -0400
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Tejun Heo <htejun@gmail.com> wrote:
>> Q: Does the fact that I'm using the GART IOMMU mean that I'm not really using
>> using 64-bit DMA at all?
>
> Can you turn it off and see what happens?

I can if I can verify that every other bus-master PCI device in the
system can do 64-bit DMA.

Do you know how to check that?  I haven't found a file under /sys or
/proc that tells me what the DMA masks are of various system
drivers, but that doesn't mean that it doesn't exist.

Thanks.