From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH 3/20][BNX2]: Add 40-bit DMA workaround for 5708.
Date: Wed, 02 May 2007 15:50:34 -0700 (PDT)
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From: Christoph Hellwig <hch@infradead.org>
Date: Wed, 2 May 2007 23:48:58 +0100

> On Wed, May 02, 2007 at 01:02:41PM -0700, Michael Chan wrote:
> > Let's say I have a 32-bit card that cannot do dual address cycle on a
> > 64-bit dma_addr_t system without IOMMU.  If CONFIG_HIGHMEM is not set,
> > wouldn't the device get > 32-bit DMA addresses that it cannot handle?
> 
> It needs to set it's dma mask to 32bits and the upper layers (net, block)
> will do the bouncing for it.  

Not the case for networking, we rely upon the DMA API to take
care of things, which it does.