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Subject: Re: PPC64 & DMA zone
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Tabi Timur-B04825 <B04825@freescale.com>
Date: Sun, 02 Sep 2012 13:12:48 +1000
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 Aaro Koskinen <aaro.koskinen@iki.fi>
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On Sun, 2012-09-02 at 02:54 +0000, Tabi Timur-B04825 wrote:
> On Fri, Aug 17, 2012 at 3:40 PM, Benjamin Herrenschmidt
> <benh@kernel.crashing.org> wrote:
> > On Fri, 2012-08-17 at 23:04 +0300, Aaro Koskinen wrote:
> >> Hi,
> >>
> >> Is there a way to reduce/limit DMA zone with PPC64 kernel (3.6-rcX)
> >> on G5 Mac? I have tried to search Kconfig or command line options,
> >> but can't find anything.
> >
> > No.
> 
> What about Shaohui patches for ZONE_DMA?  That's meant to solve
> exactly this problem?  Granted, it sets the DMA zone to 31 bits, but
> it's simple to hack that to 30 bits.

Unnecessary for this specific problem. The right fix to the iommu code
has already been done.

Cheers,
Ben.