Re: [PATCH v3] ad7877: keep dma rx buffers in seperate cache lines

[Mike Frysinger]

On Tue, May 11, 2010 at 16:38, Pekka Enberg wrote:
> Mike Frysinger wrote:
>> that is a question for David/Grant. Âi'm not the SPI core maintainer,
>> i'm merely watching over some SPI drivers. Âhowever, this answer also
>> doesnt sound like it's thinking big enough because what you're
>> proposing isnt specific to the SPI bus -- any time a DMA safe buffer
>> is needed dynamically, this function could be used.
>
> Well, we have dma_alloc_coherent(), shouldn't you be using that instead?

my understanding is that dma_alloc_coherent() gives you a buffer that
is always coherent.  the SPI layers take care of flushing and such on
the fly which means allocating coherent memory is overkill and bad for
performance.
-mike
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/