module-suspend-on-idle suspending active pci sound card
Summary
module-suspend-on-idle is suspending pci cards when they are actually active.
environment
Steps to reproduce
1: have a pci sound card.
2: have module-suspend-on-idle active.
3: play audio with some common software, like vlc of firefox. There should be no audio.
4: open pavucontrol or audacity, audio will be played.
5: close pavucontrol/audacity, audio will stop playing after a few seconds.
6: disable module-suspend-on-idle, restart pulseaudio.
7: audio should be played now regardless of having pavucontrol or audacity open.
Extra info: the sound can be played directly through the card without going through pulse audio. HDMI audio isn't affected by it. I experienced this bug on my other machine running ubuntu 18 with pulseaudio 11.1 too. Both machines either have or had a pci-e graphics card with hdmi installed at some point, both machines can't output sound through the onboard sound card. This machine running centos stopped being able to output sound through the onboard card after I installed the pci-e graphics card, this problem persisted even after removing the pci-e graphics card.