Changing screen resolution changed my audio sink from headphones to the speakers in my monitor

[spike speigel]

I changed my screen resolution from 2560x1440 to 1024x768 to test an application, and my audio sink was switched from headphone output to the speakers in my monitor for all applications playing sound.

I can repeatedly cause the resolution down-scaling to change my audio sink from "Built-in Audio Analog Stereo" to "GP104 High Definition Audio Controller Digital Stereo (HDMI 2)". As the sound can be carried through HDMI, maybe something with the resolution change is causing the device/sink to be re-detected and my system defaults to it. This does not appear to be happening when I up-scale my resolution e.g. going from 1024x768 to 2560x1440.

Monitor: LG 27UD58P-B
Video Card: MSI GEFORCE GTX 1070 AERO ITX 8G

ProblemType: Bug
DistroRelease: Ubuntu 19.10
Package: xfce4-settings 4.14.1-1ubuntu1
ProcVersionSignature: Ubuntu 5.3.0-26.28-generic 5.3.13
Uname: Linux 5.3.0-26-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu8.3
Architecture: amd64
CurrentDesktop: XFCE
Date: Fri Jan 3 17:29:52 2020
ExecutablePath: /usr/bin/xfce4-settings-manager
InstallationDate: Installed on 2019-03-07 (302 days ago)
InstallationMedia: Xubuntu 18.10 "Cosmic Cuttlefish" - Release amd64 (20181017.2)
ProcEnviron:
 LANGUAGE=en_US
 PATH=(custom, user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: xfce4-settings
UpgradeStatus: Upgraded to eoan on 2019-08-19 (137 days ago)

[spike speigel (frail-knight)]

I changed my screen resolution from 2560x1440 to 1024x768 to test an application, and my audio sink was switched from headphone output to the speakers in my monitor for all applications playing sound.

I can repeatedly cause the resolution down-scaling to change my audio sink from "Built-in Audio Analog Stereo" to "GP104 High Definition Audio Controller Digital Stereo (HDMI 2)". As the sound can be carried through HDMI, maybe something with the resolution change is causing the device/sink to be re-detected and my system defaults to it. This does not appear to be happening when I up-scale my resolution e.g. going from 1024x768 to 2560x1440.

Monitor: LG 27UD58P-B
Video Card: MSI GEFORCE GTX 1070 AERO ITX 8G

[Andreldm-2 (andreldm-2)]

This sounds (pun intended) more like a problem with Pulseaudio as display settings is mostly just a xrandr frontend.
Try changing the resolution with xrandr from terminal, e.g. xrandr --output HDMI-0 --mode 1024x768

[spike speigel (frail-knight)]

Had to guess around the HDMI-# but:

xrandr --output HDMI-1 --mode 1024x768

had the same effect. So it seems this is PulseAudio not remembering the previously used sink when the output device disappears/reappears?

[Andreldm-2 (andreldm-2)]

(In reply to Robert from comment #2)
> had the same effect. So it seems this is PulseAudio not remembering the
> previously used sink when the output device disappears/reappears?

Possibly, but I also noticed that restarting xfce4-panel sometimes changes the output from HDMI to the onboard sound card. Do you have pulseaudio-plugin on your panel? If so, try removing it to see if there is any difference.

[spike speigel (frail-knight)]

Yes, removing the pulseaudio-plugin from my panel prevented the switch of sound sinks when the resolution changed. :)