This certainly sounds like it's related to the nouveau driver. Are you still able to reproduce this behavior in 22.04?
** Changed in: xubuntu-meta (Ubuntu) Status: New => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1886129 Title: xubuntu : displays have become blank & unusable To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xubuntu-meta/+bug/1886129/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs