libmutter-fix is a script to download, modify, and recompile libmutter in order to apply a 'bandaid' for a bug where the XkbNewKeyboardNotify event causes the system to freeze for several milliseconds when writing input to /dev/uinput.
This happens when using multiple input devices, or in my case, when simulating input with a program (eg. macros).
This bug is not existant in Wayland nor non-GNOME-based desktop managers (from what I hear).
This script is derived completely from a post here by Osvald Lindholm - so shoutouts to them for the initial steps.
Additional threads found during my research on this bug:
- https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1777708
- https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/833
- https://gitlab.gnome.org/GNOME/mutter/-/issues/398
NOTE: The original fix was reverted because it apparently causes issues on some non-QWERTY keyboards. I cannot confirm or deny this, as it doesn't affect me.
WARNING: Use this at your own risk. I created it for my own purposes so I can keep an up-to-date version of libmutter. If the script fails or you wish to fix this issue yourself, just follow the steps listed in the initial link above.
Must be on a Debian-based distro using x11.
Run python libmutter-fix.py, let it run, then reboot.
You can use xdotool key q as a quick way to see if you suffer from the lag. Your system should lock up for a noticable amount before posting the key.
Run this command again after applying the fix and rebooting, and there should be no more system freeze.
- Pop!_OS 21.xx
- Pop!_OS 22.04