[pulseaudio-discuss] [BUG?] I get a profile with 2 outputs, but if I mute headphone it mutes both ports

[Tanu Kaskinen]

On Sat, 2015-10-31 at 01:56 +0100, GMAIL wrote:
> Hi everyone and thank you all for your efforts towards making a good 
> audio server for our loved platform.
> 
> _*My setup:*_
> 
>  > Desktop
>  > Arch Linux
>  > PulseAudio 7.1
> 
> Using motherboard embedded sound system.
> 
> _Rear:_ 3 regular jacks: red, green, blue
> -> Red jack: Mic connected
> -> Green Jack: Main speakers (Stereo)
> 
> _Front:_ 2 regular jacks: Mic and Headphones
> 
> Also, monitors speakers connected through HDMI to NVIDIA GTX 780.
> 
> _*Goal:*_ This may not be straight forward from the title but I want
> to 
> be able to listen to my headphones *only*. Currently, this is not 
> possible unless I turn off my speakers.
> 
> _*Initial situation: *__*
> *_
> Sound goes through speakers only, all good.
> 
> _*What I do:
> 
> *_I plug in my headphones.
> 
> Sound goes through speakers only, all good.
> 
> I go into PAVU, switch from "Line Out" to my headphones in front of 
> "Port" under the MOBO sink name in "Output Devices".
> 
> _*What happens:*_
> 
> The sound now goes through BOTH my speakers AND my headphones while I
> expect it to be output only to my headphones.
> 
> _*What I try:*_
> 
> I switch back to Line Out port.
> 
> Sound goes through speakers only, all good.
> 
> I mute Line Out port. It mutes instantly, all good.
> 
> I switch again to my headphones: Sound goes through *BOTH* my
> speakers 
> *AND* my headphones**again.
> 
> I switch back to the Line Out port: it is still muted, no sound from 
> either speakers or headphones.
> 
> I switch to my headphones: faulty behaviour continues, sound through
> all 
> ports, speakers and headphones alike.
> 
> I switch back to Line Out port and unmute it: sound goes through the 
> speakers only, normal.
> 
> I switch to the headphones: sound output through both speakers and 
> headphones.
> 
> I mute the headphones port: no sound through either the speakers or
> the 
> headphones. Both ports are muted.
> 
> _*Questions:*_
> 
> Is this expected behaviour?
> 
> How do I have the sound go through the selected port ONLY?
> 
> Thanks in advance for your help.

I suspect that the "Front" volume and mute elements can be used to
control the line out without affecting the headphones. The problem is
that PulseAudio's alsa configuration assumes that the "Front" element
affects both line out and headphones (there's a comment saying that "on
some machines Front is actually a part of the Headphone path").

/usr/share/pulseaudio/alsa-mixer/paths/analog-output-headphones.conf
contains this:

    [Element Front]
    switch = mute
    volume = zero

If you change that to

    [Element Front]
    switch = off
    volume = off

does that fix the problem for you?

-- 
Tanu