I'm having a little trouble with sound on my Ubuntu 18.04 system. For setup, first, I've installed default Ubuntu, then xfce-desktop, then kde-desktop.
Now, since I'm doing development, I normally graphically login as root. So when I work with gnome, and want some sound, I have to manually start pulseaudio.
So far, so little of a problem. But after installing KDE, I have no countrol over sound on the audio applet/symbol/widget.
I can also start pulseaudio manually, and start pavucontrol, but I get no devices there, other than the dummy device.
The funny thing is, sound works, just that I can't control the volume with the kde volume manager/applet/symbol/widet. There's also no pulseaudio-daemon running. I've killed them all, and the sound still works - so I assume it somehow runs on ALSA.
Now when I plugin the headphones - it mutes, and I can't unmute. I've discovered I can change the volume on the console with "alsamixer". But I can't unmute the headphones there. I turn-up the headphone volume on alaxamixer, and it's still muted.
Anybody knows how I can unmute the headphones with ALSA, or why else it doesn't work ?
Or how/where I can switch between ALSA and pulseaudio ?
And how can I see what the system is using ?