[alsa-devel] Separate input and output jacks for one UCM device?

[Tanu Kaskinen]

On Tue, 2015-04-07 at 23:37 +0300, Tanu Kaskinen wrote:
> On Thu, 2015-04-02 at 08:28 -0700, Dylan Reid wrote:
> > On Wed, Apr 1, 2015 at 5:27 AM, Liam Girdwood
> > <liam.r.girdwood at linux.intel.com> wrote:
> > > On Tue, 2015-03-31 at 19:49 +0300, Tanu Kaskinen wrote:
> > >> So is your preference that UCM configuration authors are forced to
> > >> define simplex devices to deal with headset jacks, rather than using
> > >> duplex devices and defining "PlaybackJackControl" and
> > >> "CaptureJackControl" separately? (I don't personally mind either way.)
> > >
> > > I don't really mind either, but what's easier for audio servers like
> > > pulseaudio that will be the main UCM clients ? I guess that pulseaudio,
> > > CRAS, and other audio servers probably deal with simplex PCM streams
> > > internally so mapping to simplex jacks/devices might be better ?
> > 
> > There is an advantage to having a separate device for the headphone and mic
> > even if they are connected to the same jack.  The user can enable one and not
> > the other, most commonly to use the headphones but record from the built-in mic,
> > ignoring the headset mic.  Because of this we require all ChromeOS devices to
> > support separate reporting and selection of headphone/mic on the headset jack.
> > There is always one UCM device and one user-visible i/o node per jack.
> 
> I'm not sure what you mean... "There is always one UCM device [...] per
> jack" sounds like you want there to be only one device representing
> headset, but on the other hand you talk about it being advantageous to
> have a separate device for the headphone and mic... Can you clarify the
> number of UCM devices per physical headset jack?

Ping? I'd like to get this clarified, because depending on what CRAS
does, we may or may not have to change the use-case.h documentation (and
PulseAudio code).

-- 
Tanu