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

[Takashi Iwai]

At Thu, 19 Mar 2015 15:18:51 +0000,
Mark Brown wrote:
> 
> On Thu, Mar 19, 2015 at 03:51:06PM +0100, Takashi Iwai wrote:
> > Mark Brown wrote:
> 
> > > The theory is that this is handled by the fact that the userspace ABI
> > > includes a reference to the struct device and therefore a chain showing
> > > where the thing is attached; anything registering two different jacks
> > > with the same name attached to the same device probably qualifies as
> > > broken.
> 
> > So this implicitly assumes the name uniqueness.  For HD-audio, this
> > was a problem because we need to generate jack names dynamically; for
> > example, there are laptops with two headphones, and we assigned
> > indices in such a case.
> 
> That's on the same card, though?

Yeah, on the same laptop, even both on the front.  The designer must
have smoked, or just looked for a partner sitting at next to listen to
music together :)

> I'd expect a device creating two input
> jacks to do the same (putting the number in the name, or some other
> identifer like "front" and "back").

Yes, stringifying the index number would work.


Takashi