From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
To: Alexis Berlemont <alexis.berlemont@domain.hid>
Cc: Xenomai help <xenomai@xenomai.org>
Subject: Re: [Xenomai-help] Command code working with comedi not working with analogy
Date: Wed, 12 Oct 2011 00:21:48 +0200 [thread overview]
Message-ID: <4E94C17C.2080702@domain.hid> (raw)
In-Reply-To: <CAMesUR5PsVLb16ZR1bdcbDWdUfvPxViPng+rD7mjQqy1q+OGfA@mail.gmail.com>
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.
next prev parent reply other threads:[~2011-10-11 22:21 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-27 18:55 [Xenomai-help] Command code working with comedi not working with analogy Fernando Herrero Carrón
2011-09-27 21:02 ` Gilles Chanteperdrix
2011-09-28 7:33 ` Julien Delange
2011-09-28 15:19 ` Fernando Herrero Carrón
2011-09-29 19:57 ` Fernando Herrero Carrón
2011-09-29 22:16 ` Alexis Berlemont
2011-10-03 21:41 ` Fernando Herrero Carrón
2011-10-04 20:29 ` Fernando Herrero Carrón
2011-10-05 21:16 ` Alexis Berlemont
2011-10-05 23:06 ` Fernando Herrero Carrón
2011-10-06 18:49 ` Fernando Herrero Carrón
2011-10-06 21:31 ` Alexis Berlemont
2011-10-06 22:18 ` Fernando Herrero Carrón
2011-10-07 22:06 ` Alexis Berlemont
2011-10-10 15:27 ` Fernando Herrero Carrón
2011-10-11 22:12 ` Alexis Berlemont
2011-10-11 22:21 ` Gilles Chanteperdrix [this message]
2011-10-11 23:08 ` Alexis Berlemont
2011-10-12 16:00 ` Fernando Herrero Carrón
2011-10-12 19:13 ` Fernando Herrero Carrón
2011-09-28 15:37 ` Fernando Herrero Carrón
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