[alsa-devel] What is exact definition of "normal/inverted" FSYNC signal polarity?

[Anatol Pomozov]

Hi Mark

On Tue, Sep 1, 2015 at 5:14 AM, Mark Brown <broonie at kernel.org> wrote:

> On Mon, Aug 31, 2015 at 12:05:51PM -0700, Anatol Pomozov wrote:
>
> > Thus "normal" FSYNC for this driver means that the frame (L channel)
> > starts at rising edge of FSYNC (wm8731 datasheet calls it DACLRC).
> > "inverted" means frame starts at the falling edge. It differs both
> > from TegraX1 and rt5677 above.
>
> > It looks like each driver uses its own definition of FSYNC polarity.
> > To avoid compatibility problems between different codecs/socs there
> > should be a clean definition of what is FSYNC polarity is. I would
> > propose something simple like:
> >     ****  "normal" FSYNC means frame starts at rising edge of FSYNC,
> > and "inverted" frame starts at falling FSYNC edge ****
> > i.e. the same as for 8731.
>
> Right, the Tegra and Realtek drivers are buggy here - the wm8731
> definition is the one that essentially everything is using.
>

Are you OK to accept the patch
http://mailman.alsa-project.org/pipermail/alsa-devel/2015-August/097126.html
 ?

If yes then I will work with NVidia/Realtek on updating their drivers.