I've just experienced this problem (or very similar) on a fresh install of Xubuntu 20.04, on a Thinkpad x240.
On wake, I could move the mouse, and switch to a virtual console with ctrl-alt-f1. The session would sometimes animate for a moment (e.g. a notification about change in wifi), before freezing completely (except for mouse). I did not try killing/restarting any sessions. This happened both when selecting sleep then pressing the power button to wake, and when sleeping by closing the laptop lid and opening to wake. The laptop was plugged into AC power the entire time. The problem persisted across reboots, but stopped occurring (seemingly) when I rebooted, then unplugged the laptop from AC power. I can now wake successfully with the laptop both plugged and unplugged. Haven't tried rebooting again since. I have no proprietary drivers installed. `sudo lshw -C display`: *-display description: VGA compatible controller product: Haswell-ULT Integrated Graphics Controller vendor: Intel Corporation physical id: 2 bus info: pci@0000:00:02.0 version: 0b width: 64 bits clock: 33MHz capabilities: msi pm vga_controller bus_master cap_list rom configuration: driver=i915 latency=0 resources: irq:50 memory:e0000000-e03fffff memory:c0000000-dfffffff ioport:3000(size=64) memory:c0000-dffff Attached config files, which might contain relevant power manager settings. ** Attachment added: "The contents of ~/.config/xfce4/xfconf" https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1605813/+attachment/5360220/+files/xfconf.tar.gz -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to lightdm in Ubuntu. https://bugs.launchpad.net/bugs/1605813 Title: lock screen freezes while trying to wake from suspend Status in lightdm package in Ubuntu: Confirmed Bug description: Background: I am running a fully updated 16.04.1 installation of Ubuntu using open source nVidia drivers. When I press the power button on my PC to wake the computer from suspend, the login screen appears and freezes. The box around my username becomes somewhat opaque and no text box that would allow me to enter my password appears. I have tried this many times, and it always locks up in the same way. Steps taken after issue occurs: I have found, however, that the system is not completely locked up. I can use CTL + ALT + F2 to switch to TTY2. From there I can login and restart the computer without issue. I also tried restarting lightdm via sudo service lightdm restart. When I tried this and switched back to the GUI, the login screen was loaded, and I could type my password. Once the login screen disappeared, one of my monitors (dual-monitor setup) switched to my user account's wallpaper, and then the system locked up. I had to perform a hard restart. Workaround: I have found that using the proprietary 361.42 drivers provides a work around for this issue. When using the proprietary drivers, the computer resumes from suspend without issue. ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: lightdm 1.18.2-0ubuntu1 ProcVersionSignature: Ubuntu 4.4.0-31.50-generic 4.4.13 Uname: Linux 4.4.0-31-generic x86_64 ApportVersion: 2.20.1-0ubuntu2.1 Architecture: amd64 CurrentDesktop: Unity Date: Fri Jul 22 20:53:10 2016 EcryptfsInUse: Yes InstallationDate: Installed on 2016-07-08 (14 days ago) InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1) ProcEnviron: LANGUAGE=en_US PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: lightdm UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1605813/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp