[alsa-devel] pxa2xx-pcm and dma_request

Dmitry Eremin-Solenikov dbaryshkov at gmail.com
Wed May 13 06:43:05 CEST 2009

2009/5/13 Robert Jarzmik <robert.jarzmik at free.fr>:
> Hi Mark and Dimitry,
> I've been playing for some time with DMA on the PXA series. I was wondering if
> the behaviour of pxa2xx-pcm is correct.
> As far as I understand, in an asoc context, the __pxa2xx_pcm_open() is called,
> while in "arm context", pxa2xx_pcm_open() is called, which calls
> __pxa2xx_pcm_open().
> This was introduced by commit a6d77317678148c973bb0131cc5a3a772f756d23 I think.
> One main difference is that in "arm context", pxa_dma_request() is called, while
> in "asoc context", it is not.

This was done by intent as before code merge plain ARM driver used DMA while
ASoC didn't. That was done mainly because I didn't have all the hw
variants (only
pxa255 at hand) and didn't want to introduce any points of possible failure.
Now merging DMA code into generic code path would be a nice feature though.

> I'd like one of you to cross-check, as I must admit I'm not following all the
> impacts of the pcm code split-up.

The initial impact of the merge should be void, as it was an
_unification_ of code
presented in ASoC and non-ASoC drivers.

With best wishes

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