[pulseaudio-discuss] PulseAudio, switch audio output on device connection

[Mark Gaiser]

On Wed, Oct 8, 2014 at 1:06 PM, Tanu Kaskinen <tanu.kaskinen at linux.intel.com>
wrote:
> On Mon, 2014-10-06 at 19:47 +0200, Mark Gaiser wrote:
>> Ok, i tried a bunch of different players. The results:
>> - mplayer (smplayer as well) : sound doesn't switch when attaching a
headphone
>> - rhythmbox : refused to play any plain simple mp3 file
>> - amarok : sound doesn't switch when attaching a headphone
>> - dragon player : sound doesn't switch when attaching a headphone
>> ...
>>
>> I did get rhythmbox to beep once and that one came out of my headset.
>> Based on that i'm beginning to think that there is some GTK vs Qt
>> difference in play here.
>>
>> One thing i did found (in the kde settings) was that i can prefer my
>> headphone to be first in sound order. Funny thing is, this is actually
>> working for an application like amarok which then behaves as i expect.
>> However, other apps don't seem that happy to comply and just spew out
>> audio to my jack port.
>
> There shouldn't be that kind of differences between apps, unless you
> have previously moved manually those applications around. What if you
> clear the pulseaudio state by doing this:
>
> - disable autospawning (so that you can be sure pulseaudio isn't running
> during the next steps):
>     cat "autospawn = no" >> ~/.config/pulse/client.conf
>
> - killall pulseaudio
>
> - remove all files under ~/.config/pulse except client.conf
>
> - restart pulseaudio:
>     pulseaudio -D
>
> - load module-switch-on-connect:
>     pactl load-module module-switch-on-connect
>
> Is there still a difference in behaviour between amarok and other
> applications?
>
> Since you use kde, the routing may be a bit different than on my
> machine, if you have module-device-manager loaded, and that might
> explain the general problem of the automatic routing not working as
> expected. When you start your kde session, module-device-manager gets
> loaded. On gnome, for example, that module is not loaded by default.
> Just restarting pulseaudio while the session is running should get rid
> of module-device-manager, because it's only loaded when the session
> starts, but you can of course always unload it with "pactl unload-module
> module-device-manager". You can verify that the module is not loaded by
> running "pactl list modules short". If module-device-manager isn't
> listed, then it isn't loaded.
>
>> Could you perhaps test if you can get the same thing working under
mplayer?
>> mplayer -ao pulse <some_mp3_file>
>>
>> That is a quite simple test - easy to reproduce - and doesn't give me
>> the expected result. I wonder how that works with you.
>
> Works fine.
>
> --
> Tanu
>

And reporting back with my findings.

First i verified if the module "module-device-manager" would be loaded.
It's not so that's probably not an issue.
Then i followed your steps and it - amazingly - worked! However, with a
issue.

If i play a sound file (using mplayer as a test case) it:
- plays from my speakers by default (OK!)
- If i attach my (usb) headset the sound moves to the headset. Happy me :)
- If i detach my usb headset again the sound isn't being played anywhere
anymore. Attaching/detaching many more times doesn't help either.

I also think i know why it happens, just not a solution to the issue.
If i type "pactl list short sinks" i get this output when my headset is not
attached:

0       alsa_output.pci-0000_01_00.1.hdmi-stereo        module-alsa-card.c
     s16le 2ch 44100Hz       SUSPENDED
1       alsa_output.pci-0000_00_1b.0.analog-stereo      module-alsa-card.c
     s16le 2ch 44100Hz       SUSPENDED

When i play a file the list changes:

0       alsa_output.pci-0000_01_00.1.hdmi-stereo        module-alsa-card.c
     s16le 2ch 44100Hz       SUSPENDED
1       alsa_output.pci-0000_00_1b.0.analog-stereo      module-alsa-card.c
     s16le 2ch 44100Hz       RUNNING

So far so good. I have no HDMI devices attached that can play sound (a
projector is attached. It can beam video, not audio :)

When attaching the headset i get:
0       alsa_output.pci-0000_01_00.1.hdmi-stereo        module-alsa-card.c
     s16le 2ch 44100Hz       SUSPENDED
1       alsa_output.pci-0000_00_1b.0.analog-stereo      module-alsa-card.c
     s16le 2ch 44100Hz       IDLE
7
alsa_output.usb-Corsair_Components__Inc._Corsair_Vengeance_1500-00-C1500.analog-stereo
 module-alsa-card.c      s16le 2ch 44100Hz       RUNNING

Note the added usb headset and it is running now. All perfectly fine thus
far.
But when i detach my headset the list becomes wrong:

0       alsa_output.pci-0000_01_00.1.hdmi-stereo        module-alsa-card.c
     s16le 2ch 44100Hz       RUNNING
1       alsa_output.pci-0000_00_1b.0.analog-stereo      module-alsa-card.c
     s16le 2ch 44100Hz       SUSPENDED

Note the hdmi sink is now suddenly playing the sound!
I would expect the sink to continue device that was sitting idle, but
somehow it picked the other device.
Did i actually find a bug just now or is this also some magic setting that
i can change somewhere?

If i re-attach my usb headset again the audio isn't send there anymore. It
keeps sending it to the hdmi device:

0       alsa_output.pci-0000_01_00.1.hdmi-stereo        module-alsa-card.c
     s16le 2ch 44100Hz       RUNNING
1       alsa_output.pci-0000_00_1b.0.analog-stereo      module-alsa-card.c
     s16le 2ch 44100Hz       SUSPENDED
10
 alsa_output.usb-Corsair_Components__Inc._Corsair_Vengeance_1500-00-C1500.analog-stereo
 module-alsa-card.c      s16le 2ch 44100Hz       IDLE

Thank you very much for your help thus far. It really helped me greatly!
Looks like we're nearly there :)
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