[alsa-devel] [PATCH v7] ASoC: omap-mcbsp: Add PM QoS support for McBSP to prevent glitches

[Matt Ranostay]

On Tue, Jan 17, 2017 at 4:34 AM, Peter Ujfalusi <peter.ujfalusi at ti.com> wrote:
> On 01/16/2017 09:30 PM, Matt Ranostay wrote:
>> Yep I was testing with that enabled. Not sure why I'm not getting it
>> all... maybe different side effects like sample rate of the audio
>> being played?
>>
>> Peter, is there chance that there is race condition is possible
>> between pm_qos_remove_request and omap_mcbsp_dai_shutdown?
>
> Not with my knowledge.
> However one thing might happen which is not handled:
> application opens up the audio card, does some hw_param setup, then it
> decides to close the card. In this case the pm_qos is not placed, but in
> dai_shutdown we try to remove it -> WARN().
>
> I think we need to check either if the pm_qos is active and only then
> bother with the removal/updated or we can check if the
> mcbsp->latency[stream1] is not 0, which should be the same as checking
> for the pm_qos active

Ok makes sense. Weird I'm not seeing it but I wanted to be sure adding
checks wasn't just hiding a issue.
Will submit v8...  and hopefully that is the final one! *fingers crossed*

>
> --
> Péter