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From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Aaro Koskinen <aaro.koskinen@iki.fi>
Cc: linuxppc-dev@ozlabs.org
Subject: Re: PPC64 & DMA zone
Date: Sat, 18 Aug 2012 06:40:56 +1000	[thread overview]
Message-ID: <1345236056.11781.1.camel@pasglop> (raw)
In-Reply-To: <20120817200406.GA1908@harshnoise.musicnaut.iki.fi>

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.

> The problem I have is that b43 driver (wireless chip) insists a 30-bit
> DMA mask, but I have 1.5 GB physical memory. So the only way I can get
> the wireless connection to work is to boot with "mem=1024MB". And as a
> result my bloaty applications will loose much needed memory...

Or force the iommu to be enabled, it should be able to service
constrained DMA (iommu=force on the command line).

Cheers,
Ben.

  reply	other threads:[~2012-08-17 20:41 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-17 20:04 PPC64 & DMA zone Aaro Koskinen
2012-08-17 20:40 ` Benjamin Herrenschmidt [this message]
2012-08-17 21:01   ` Aaro Koskinen
2012-08-17 21:38     ` Benjamin Herrenschmidt
2012-09-02  2:54   ` Tabi Timur-B04825
2012-09-02  3:12     ` Benjamin Herrenschmidt

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