pulseaudio issue on QEMU/KVM guest VM when microphone is replugged/unplugged pulseaudio: pa_threaded_mainloop_lock failed pulseaudio: Reason: Invalid argument

Here is the scenario, you are using QEMU/KVM and are using something like the AC97 sound driver to pass the host audio to the guest via pulseaudio.  This is useful because you can transparently pass your mic input from the host which means you can mute your microphone from the host, which prevents the guest from receiving any mic input even if unmuted.

Mute / Unmute Fix

This issue also seems to happen even if you press the mute button on the microphone and then unmute, it has virtually the same effect as unplugging and replugging the USB microphone.

One thing that seems to help with muting and unmuting button issue, is if you set your Microphone as a single input only (no dual input/output / duplex).

In Mint/Ubuntu, it means going to Sound Settings, Hardware, clicking on your Microphone and just choosing "Input"


Here is the relevant CLI that makes this audio config happen that gets passed to QEMU:

-audiodev driver=pa,id=pa1,server=unix:/run/user/1000/pulse/native -device intel-hda -device AC97,audiodev=pa1

You would change the /run/user/1000 with your numeric uid which can be retrieved with id -u

But the problem is that input/mic audio will break (note that output is unaffected though) on the guest if there is any change to the pulseaudio on the host side during this time:

You will get pulseaudio errors like this:

pulseaudio: pa_threaded_mainloop_lock failed
pulseaudio: Reason: Invalid argument
pulseaudio: pa_threaded_mainloop_lock failed
pulseaudio: Reason: Invalid argument
pulseaudio: pa_threaded_mainloop_lock failed
pulseaudio: Reason: Invalid argument


I am not aware of any solution for this other than to hard restart the guest VM (not just a graceful reset initiated from the VM but a full hard poweroff of the VM).

One other config that I have tried is to use the -device hda-duplex but this seems to be buggy as shortly after starting the VM, mic audio input seems to fail on the guest which means the mic stops working.  This is why I use AC97, as it seems to be persistent so long as you don't unpug the microphone (config CLI below).

-audiodev driver=pa,id=pa1,server=unix:/run/user/1000/pulse/native -device intel-hda -device hda-duplex,audiodev=pa1


pulseaudio, qemu, kvm, vm, microphone, replugged, unpluggedhere, ac, audio, via, transparently, mic, input, mute, prevents, receiving, unmuted, relevant, cli, config, audiodev, server, unix, user, native, intel, hda, numeric, uid, retrieved, output, unaffected, errors, pa_threaded_mainloop_lock, invalid, restart, graceful, reset, initiated, poweroff, duplex, buggy, persistent, unpug,

Latest Articles

  • LXC Containers LXD How to Install and Configure Tutorial Ubuntu Debian Mint
  • Ubuntu Mint audio output not working pulseaudio "pulseaudio[13710]: [pulseaudio] sink-input.c: Failed to create sink input: too many inputs per sink."
  • How To Shrink Dynamically Allocated VM QEMU KVM VMware Disk Image File
  • How To Enable Linux Swapfile Instead of Partition Ubuntu Mint Debian Centos
  • 404 Not Found [IP: 80] apt update Debian 11 Bullseye Solution The repository 'http://security.debian.org bullseye/updates Release' does not have a Release file.
  • WARNING: Can't download daily.cvd from db.local.clamav.net freshclam clamav error solution
  • (firefox:9562): LIBDBUSMENU-GLIB-WARNING **: Unable to get session bus: Failed to execute child process "dbus-launch" (No such file or directory) Solution
  • Debian Mint Ubuntu Which Package Provides missing top, ps and w Solution
  • Vbox Virtualbox DNS NAT Network Mode NOT working
  • Docker Tutorial HowTo Install Docker, Use and Create Docker Container Images Clustering Swarm Mode Monitoring Service Hosting Provider
  • Zoom Password Error 'That passcode was incorrect' - Solution Wrong Passcode Wrong Meeting Name
  • How To Startup and Open Remote/Local Folder/Directory in Ubuntu Linux Mint automatically upon login
  • How To Reset Windows Server Password 2019, 2022, 7, 8, 10, 11 Recovery and Removal Guide Using Linux Ubuntu Mint Debian
  • How To Create OpenVPN Server for Secure Remote Corporate Access in Linux Debian/Mint/Ubuntu with client public key authentication
  • HongKong VPS Server, Cloud, Dedicated Server, Co-Location, Datacenter The Best Guide on Hong Kong, China Internet IT/Computing
  • ssh-keygen id_rsa private key howto remove the passphrase so no password is required and no encryption is used
  • Package wget is not available, but is referred to by another package. This may mean that the package is missing, has been obsoleted, or is only available from another source. E: Package 'wget' has no installation candidate. Solution
  • tag#4 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE tag#4 Sense Key : Illegal Request [current] res 40/00:b4:98:02:00/00:00:00:00:00/40 Emask 0x10 (ATA bus error) solution
  • Wazuh Install and Configuration Howto Tutorial Guide for Monitoring Agents
  • Linux Debian How To Enable Sudo/Sudoers for User "User not in sudoers file" Solution