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Subject: Re: [PATCH V2 2/3] powerpc: Add support for swiotlb on 32-bit
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Kumar Gala <galak@kernel.crashing.org>
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Date: Tue, 19 May 2009 07:49:55 +1000
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On Mon, 2009-05-18 at 08:25 -0500, Kumar Gala wrote:
> 
> Part of this is how the generic swiotlb code works and part of it
> was  
> our desire not to bloat dev archdata by adding such info that as you  
> say is either bus specific or conveyed in the dma addr mask.

Right but perf sucks :-)

Maybe an option is to clamp the DMA mask when it's set by the driver to
limit it to the available inbound window ?

Cheers,
Ben.