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Date: Wed, 12 Oct 2011 00:21:48 +0200
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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Subject: Re: [Xenomai-help] Command code working with comedi not
 working	with analogy
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To: Alexis Berlemont <alexis.berlemont@domain.hid>
Cc: Xenomai help <xenomai@xenomai.org>

On 10/12/2011 12:12 AM, Alexis Berlemont wrote:
> The methods are not the same at that level:
> - comedi: n * dma_alloc_coherent  + a vmap at the end
> - analogy:  a big vmalloc + n * page_to_phys(vmalloc_to_page(vaddr)

I do not know if that makes a difference, but the result of
dma_alloc_coherent is memory physically contiguous, whereas it is not
the case for memory returned by vmalloc.

dma_alloc_coherent also allows the GFP_DMA32 flag if you want 32 bits
memory.

-- 
                                                                Gilles.