Re: [FFADO-user] Presonus FirestudioMobile. Stereo support for headphones

[Jonathan W. <jw...@ju...>]

Hi Aurelien

On Sun, Jan 10, 2016 at 02:10:16PM +0100, Aurelien Martin wrote:
> First of all, best wish for this new year.

Thanks, and to you too.

> I haven't time to have a look in the code, but I don't forget when I'll
> have spare time.

All good.

> FYI: I have also a mono in the main outputs with the snd_dice driver.
> Shall I report it to alsa-devel ?

As far as I can tell the issue of mono output is one of routing.  If that's
the case then snd-dice isn't really involved.  The kernel driver only deals
with streaming audio data to and from the device.  Routing, mixer and
control remains the responsibility of user-space programs (such as but not
limited to ffado-mixer).  This separation is done for two reasons.  It keeps
considerable complexity out of the kernel, and secondly there are no
performance or other reasons for putting the control code into the kernel. 
It is also easier to write it in user-space.

So if the whole mono output is purely an issue of routing then fixing
ffado-mixer will address it.  The only time snd-dice would be implicated is
if the stereo configuration changes the streaming arrangements in some way
that are not automatically communicated to the driver by the interface.

Takashi: is the above at least vaguely correct, or are there addional
details I have missed?

Regards
  jonathan