[alsa-devel] ASoC:Question on strict sequence followed for trigger

Clemens Ladisch clemens at ladisch.de
Thu Mar 29 08:49:37 CEST 2012

gsantosh at codeaurora.org wrote:
> I see there is a strict sequence followed for trigger callback to codec
> dai, platform dai and cpu dai.
> In the below function of soc-core .
> int soc_pcm_trigger(struct snd_pcm_substream *substream, int cmd);
> In some scenarios we may require the sequence to be the other case to make
> sure the underlying DSP / codec is configured and triggered properly.

The trigger callback should do nothing but actually start the stream.
(In the ideal case, this would be setting one bit in a register of the
DMA controller.)

Any configuration should be done in hw_params.


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