[alsa-devel] [PATCH v5] ASoC: omap-mcbsp: Add PM QoS support for McBSP to prevent glitches

[Peter Ujfalusi]

On 01/10/2017 05:23 AM, Matt Ranostay wrote:
> Yeah I can reproduce the issue you are mentioning. Anyone have a
> suggestion how on to resolve? Guessing the QoS function calls need to
> be in an atomic context and the omap_mcbsp_* functions can sleep

I think it is the other way around: we call a sleeping function from
atomic context. pcm_trigger is atomic.

Most probably we should add the .prepare callback to mcbsp_dai_ops and
do the QoS update which is done in omap_mcbsp_start() there. The things
we do in omap_mcbsp_stop() then can be moved to omap_mcbsp_dai_shutdown().

I think the code would handle cases when user space stops the stream,
re-configures it and starts it with different parameters w/o closing it.

-- 
Péter