I noticed in the source code recently that power saving modes are implemented differently in atomic KMS, which only got switched on recently. Maybe try turning that off in /etc/environment to see if the problem is specific to atomic KMS:
MUTTER_DEBUG_ENABLE_ATOMIC_KMS=0 and then reboot. ** Tags added: impish -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to mutter in Ubuntu. https://bugs.launchpad.net/bugs/1929650 Title: Screen doesn't turn off when using Wayland on some devices To manage notifications about this bug go to: https://bugs.launchpad.net/mutter/+bug/1929650/+subscriptions -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs