[alsa-devel] [PATCH] ASoC: rsnd: adg :: AUDIO-CLKOUTn can synchronizes with L/R clock.

[Kuninori Morimoto]

Hi Mark

Thank you for your explanation

> > I'm now confusing. We can set system clock on audio card, for example
> > simple-card case, it is called as "system-clock-frequency".
> > In my understanding, this "system clock" and above "master clock" are same clock.
> > but "system clock" is fixed rate (= not related to audio clock in many cases).
> > Because of this, some codec doesn't request synchronous between
> > master clock <-> audio clock, but, some codec requests synchronous it.
> > Am I wrong ??
> 
> A lot of CODECs can to varying degrees tolerate this but it will tend to
> show up in performance numbers, it's often not immediately obvious just
> from a listening test.  Usually those that don't mind have a FLL or PLL
> they're using to generate the actual audio master clock at a useful rate
> for dividing down, or sometimes fancy digital logic to match things
> up.
> 
> It's not a problem to have this configurable, I'm just thinking it might
> be better to have the default be the other way around so that we default
> to synchronous but can turn that off if it's required.

OK, I see.
I checked existing DT, and default synchronous <-> asynchronous
exchange seems no problem.
So, synchronous will be default in v2