lock screen freezes while trying to wake from suspend

[Bickhaus]

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)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Alexis Scheuer (alexis-scheuer)]

The same problem appears to me after upgrading to 16.04 with an Intel card (described below), both with sleep and deep sleep: when I wake the computer, I have a normal box in the centre of the screen, the rest is darker, and no login box...

My only turn around is to log on another TTY, and stop the session (kill -9 -1).

Similar environment otherwise (16.04.01 up to date, amd64), except fr_FR and graphic card.
`sudo lshw -C display` returns (in French) *-display
       description: VGA compatible controller
       produit: 3rd Gen Core processor Graphics Controller
       fabriquant: Intel Corporation
       identifiant matériel: 2
       information bus: pci@0000:00:02.0
       version: 09
       bits: 64 bits
       horloge: 33MHz
       fonctionnalités: msi pm vga_controller bus_master cap_list rom
       configuration: driver=i915 latency=0
       ressources: irq:29 mémoire:f6400000-f67fffff mémoire:e0000000-efffffff portE/S:f000(taille=64)

[Alexis Scheuer (alexis-scheuer)]

Another detail: I use xscreensaver, not Light Locker, which works perfectly well otherwise.

And I get a normal sleep (from which I can wake the computer) when I undock my laptop (but I don't know why it turns to sleep mode in that situation).

[Alexis Scheuer (alexis-scheuer)]

Wow, that's a fast correction: for my laptop, the bug appeared yesterday, and was solved today! I am back to only one button "sleep" (under the three "logout", "reboot" or "shutdown" - sorry if the labels are not correct, these are raw translation of the French labels I get) which works, instead of the two ("sleep" and "deep sleep") which froze the laptop.

Cool, thanks for the help.

[Jorge Morais (jorgemorais)]

I too was affected by this bug. I run a fully updated 16.04 installation (currently 16.04.2) of Ubuntu. I used nouveau. When I pressed the power button on my work desktop to wake it from suspend, *sometimes* (here I differ from the original reporter) the login screen would appear and freeze. The system would not completely lock up. I could use ctrl + alt + f2 to switch to TTY2 and then restart the computer, like the original reporter.

If I tried restarting lightdm via sudo service lightdm restart, the computer would completely lock up and I had to perform a hard restart.

I successfully worked around the issue by installing the proprietary nvidia driver (nvidia-340).

[Toby Dimmick (tobydimmick)]

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.

[Toby Dimmick (tobydimmick)]

I'm experiencing this again, now without AC power (I think that was a red herring).

It seems to be if I:
- Reboot
- Close the lid (which suspends the machine)
- Reopen the list

I've also noticed that certain things still render. If I plug/unplug the AC adapter, I will continue to see "battery charging/discharging" notification popups.

Additionally, I had a log file open on the screen in VS Code. I changed the contents of this file from ctrl-alt-f1 virtual console, then switched back to my graphical session, and the displayed text in VS Code updated!

But I still could not interact with anything on-screen, beyond moving the mouse (no mouseover animations, nothing happens when clicking with touchpad or mouse, no keyboard response).

Attached dmesg output - session suspend/wake is the last ~60 lines.