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

[Takashi Iwai]

At Thu, 19 Mar 2015 14:42:40 +0000,
Mark Brown wrote:
> 
> On Thu, Mar 19, 2015 at 03:37:12PM +0100, Takashi Iwai wrote:
> 
> > The uniqueness of item name is also needed for input jack.  There is
> > no check as of now, and input drivers allow multiple items with the
> > very same name string, but user-space can't distinguish them.
> 
> 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.


Takashi