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

[Matt Ranostay]

On Mon, Jan 9, 2017 at 11:38 PM, Peter Ujfalusi <peter.ujfalusi at ti.com> wrote:
> 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().

Seems reasonable. Will rework patchset and retest.

Thanks,

Matt

>
> 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