From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Takashi Iwai <tiwai@suse.de>
Cc: linuxppc-dev@ozlabs.org, cjg@cruxppc.org
Subject: Re: [PATCH] Sam440ep support
Date: Tue, 06 May 2008 21:27:14 +1000 [thread overview]
Message-ID: <1210073234.21644.177.camel@pasglop> (raw)
In-Reply-To: <1210073153.21644.175.camel@pasglop>
> Hrm... the problem is that you aren't supposed to make up sglists with
> the result of dma_alloc_coherent... It might be a limitation of our core
> DMA API, but that's we have to deal with today..
>
> If you're going to make up sglists and call vmap, you should allocate
> pages with normal GFP. If that is a problem vs. DMA'bility of those
> pages, then ... we have a problem :-)
>
> I don't think we can easily update the DMA API at this stage. What we
> could do is provide a way to retrieve the struct page array from the
> result of dma_alloc_coherent...
Another option is to allocate the pages with gfp, and then dma_map_sg
the result... However, if we do that, we do need to add a way to vmap
with the right protection in order to get a coherent (ie. non cacheable)
mapping. I'm not even sure all archs can do that....
Ben.
next prev parent reply other threads:[~2008-05-06 11:27 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-05 18:23 [PATCH] Sam440ep support Giuseppe Coviello
2008-05-05 18:27 ` Kumar Gala
2008-05-05 19:50 ` Gerhard Pircher
2008-05-05 23:44 ` Benjamin Herrenschmidt
2008-05-06 7:51 ` Gerhard Pircher
2008-05-06 8:48 ` Benjamin Herrenschmidt
2008-05-06 9:16 ` Gerhard Pircher
2008-05-06 10:12 ` Benjamin Herrenschmidt
2008-05-06 11:14 ` Takashi Iwai
2008-05-06 11:25 ` Benjamin Herrenschmidt
2008-05-06 11:27 ` Benjamin Herrenschmidt [this message]
2008-05-06 11:31 ` Takashi Iwai
2008-05-06 11:34 ` Benjamin Herrenschmidt
2008-05-14 12:26 ` ALSA fixes for non-coherent archs (Re: [PATCH] Sam440ep support) Takashi Iwai
2008-05-14 12:50 ` Gerhard Pircher
2008-05-14 21:01 ` Gerhard Pircher
2008-05-15 5:42 ` Takashi Iwai
2008-05-19 17:23 ` Giuseppe Coviello
2008-05-20 12:48 ` Takashi Iwai
2008-05-05 23:38 ` [PATCH] Sam440ep support Benjamin Herrenschmidt
2008-05-05 18:54 ` Josh Boyer
2008-05-05 23:40 ` Benjamin Herrenschmidt
2008-05-06 0:09 ` Josh Boyer
2008-05-05 23:36 ` Benjamin Herrenschmidt
2008-05-06 4:18 ` Sean MacLennan
2008-05-06 16:37 ` Giuseppe Coviello
2008-05-09 15:53 ` Giuseppe Coviello
2008-05-09 20:26 ` Josh Boyer
2008-05-19 12:47 ` Josh Boyer
2008-05-19 15:20 ` Giuseppe Coviello
2008-05-20 12:50 ` Josh Boyer
2008-05-20 13:34 ` Josh Boyer
2008-05-22 17:51 ` Giuseppe Coviello
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