Ok, I've found the problem. This was due to a setting I had enabled in "Gnome Tweak Tool": "Suspend when laptop lid is closed" to OFF
Setting this option to OFF (the default is ON) adds an autostart link in .config/autostart/ignore-lid-switch-tweak.desktop, which runs the /usr/lib/gnome-tweak-tool/gnome-tweak-tool-lid-inhibitor utility, which creates a logind inhibitor: systemd-inhibit --list [...] Who: gnome-tweak-tool-lid-inhibitor (UID 1000/learts, PID 22291/gnome-tweak-too) What: handle-lid-switch Why: user preference Mode: block [...] "Mode: block" means that the signal is blocked and not passed to the other parts which may be handling the lid switch, including what I assume is the standard code handling the screen poweroff. By toggling the option to ON, the inhibitor goes away and the screen is turned off when I close the lid. Therefore, I advise everyone against using the "Suspend when laptop lid is closed" option in gnome tweak tools. A much better way to diisable suspend on lid cose is to edit /etc/systemd/logind.conf and set HandleLidSwitch=ignore. There are also the additional options of HandleLidSwitchDocked and HandleLidSwitchExternalPower (this one since systemd 238) to set a different action to take on lid close when the laptop is connected to an external monitor or AC power, respectively. -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to gnome-shell in Ubuntu. https://bugs.launchpad.net/bugs/1754862 Title: Screen remains active on lid close To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1754862/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs