[alsa-devel] Headphone Mic and PA

[Takashi Iwai]

On Mon, 19 Oct 2015 13:20:21 +0200,
David Henningsson wrote:
> 
> 
> 
> On 2015-10-19 11:53, Takashi Iwai wrote:
> > Hi David,
> >
> > I'm currently checking the bug report regarding PA, and this looks
> > like an issue with "Headphone Mic" jack control.
> >
> > The reported problem is that PA doesn't react properly when both HP
> > and dock line-out jacks are plugged and line-out is unplugged.  The
> > machine in question is Dell E7250, and I see that it has only
> > "Headphone Mic Jack" kctl without "Headphone Jack" kctl.  Is this the
> > intentional behavior?
> 
> Yes. The "Headphone Mic Jack" indicates that the jack can be used to 
> indicate either "Headphone" or "Mic".

Hm, OK, that was the trick.  But now I wonder whether this was a right
choice.  Maybe a more straightforward way (from user-space POV) would
have been to create two jack ctls (Headphone and Headphone Mic) and
notify both of them.

> The additional "Headset Mic 
> Phantom Jack" indicates that headset is a third usage for the jack and 
> there is no hardware that can detect which one of them it is. So it 
> looks correct to me.
> 
> Also the Dell E7250 is Ubuntu certified, but I don't think docking 
> stations are part of that certification suite (at least not for Dell E7250).
> 
> I skimmed through the opensuse bug as well. Two notes:
> 
>   1) Here's a guide of how to generate a PA log, avoiding the autospawn 
> problem: https://wiki.ubuntu.com/PulseAudio/Log
 
Yeah, but I didn't want to let user touching the config, as people
often forget to revert :)  But maybe it's better to mention it,
judging from the people's reaction.

>   2) There is a patch series in the pipeline [2] that Tanu has promised 
> to review, that makes module-switch-on-port-available more aggressive w 
> r t being able to reroute away from unavailable things. I suspect it 
> would help here, but I'm not completely sure.

The last unplug event in the log shows

D: [pulseaudio] module-alsa-card.c: Jack 'Dock Line Out Jack' is now unplugged
D: [pulseaudio] device-port.c: Setting port analog-output-lineout to status no
D: [pulseaudio] device-port.c: Setting port analog-output-speaker to status unknown

and no activation happened to analog-output-speaker.  So, yes, your
patchset might cure this.  But I wonder why this happens only with the
dock line-out and not with normal headphones...


Takashi