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Despite repeated searches I can't find anyone else reporting similar issues to me. My issue is that when I sleep my computer by closing the lid, sometimes when I open it again the screen is not locked. This is a bit of a security risk and it means that in order to guarantee my session is locked on sleep, I need to manually lock (e.g. Ctrl-Alt-L) before closing the laptop lid.

I can confirm that the computer is sleeping (i.e. I'm not mistaking the symptoms for a laptop that is failing to sleep: kernel and auth logs show lid close and open events; there is proof of sleep and wake in the logs; I can peek into the closed laptop to see that the power light and screen are off).

Furthermore I am quite confident that when I have manually locked the screen before closing the lid the screen is always locked on reopening (i.e. I don't believe the lock screen is 'dying' or failing).

My system is a Dell XPS 13 (2015 edition, 9343) running Ubuntu 16.04 LTS x64.

I really don't know what to do to investigate this and I'll gladly take any advice. I can't see any smoking gun when I compare the output of dmesg/kern.log/auth.logs/syslog between successful and unsuccessful sleep locks.

I'm really not an expert in Unity/Gnome so I'm not sure what process is responsible for the lock screen. I've seen it suggested that I should kill gnome-screensaver and run it in debug mode, however I can't see an instance of this running. When I attempt to run "gnome-screensaver --debug" under my session I get the message "WARNING **: screensaver already running in this session". I'm thinking that the advice might be out of date and that gnome-screensaver functionality has been absorbed by some other process.

So I'm currently at a loss, but very keen to solve this. Is anyone able to suggest what to try?

This problem also existed for me in 15.10, but I have not raised it until now in in case the new release fixed my issue. Sadly that did not make any difference. The 16.04 installation is fresh, not an upgrade. I cannot recall if I also experienced this in 15.04 or not.

Regards,
Bob

  • I have a similar problem, suspension only works if you tell the laptop to suspend, not by closing the lid, if after a reboot. After you order to suspend from the menu, the lid suspension works fine. Maybe this is the same bug? – lapisdecor May 7 '16 at 18:10
  • Hi lapisdecor. I can suggest a few things that I would try in your situation. First, is to check that in "Power" the action for lid close is not set to "do nothing". Next, I would poll the switch state while you test it. In terminal run "while [ true ]; do cat /proc/acpi/button/lid/LID0/state ; sleep 1; done" and close/open lid a few times, which should prove hardware switch is working. Assuming so, I would then check the auth.log for "Lid closed/opened" messages from systemd-logind. Also, you could check /etc/systemd/logind.conf to see if HandleLidSwitch has been changed from default. – Bob May 7 '16 at 20:24

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