[alsa-devel] [PATCH 2/4] ASoC: mmp: add audio dma support

[Russell King - ARM Linux]

On Tue, May 29, 2012 at 10:48:54AM +0530, Vinod Koul wrote:
> On Tue, 2012-05-29 at 13:14 +0800, zhangfei gao wrote:
> > 
> > When debugging with putting snd_dmaengine_pcm_open to probe or
> > pcm_new, there is issue.
> > snd_dmaengine_pcm_open ->
> > snd_pcm_hw_constraint_integer(substream->runtime,
> > 
> > SNDRV_PCM_HW_PARAM_PERIODS);
> > The runtime is only exist at runtime.
> > So if using soc-dmaengine, I am afraid the snd_dmaengine_pcm_open has
> > to be put in open instead of probe. 
> I think you got it wrong, the snd_dmaengine_pcm_open needs to be called
> from your CPU pcm_open. See other examples how this is used in other
> drivers.

But, as I pointed out earlier, there's the issue of using the wrong
struct device to allocate memory for the DMA engine.  That's something
that my soc-dmaengine.c got _right_, and soc-dmaengine-pcm.c gets _wrong_.