Ubuntu – Ubuntu 17.10 laptop doesn’t suspend on lid close

laptoppower-managementsuspend

Thinkpad T450 running Ubuntu 17.10 which was clean-installed (not upgraded) some weeks back. I frequently moved from room to room and like the laptop to go to sleep when I close the lid. It seems to never do this, staying awake all the time. I have to hold down the power button in the indicator and choose the pause icon to suspend it. Previous releases of Ubuntu used to "Just Work".

I have tried toggling the option in Tweaks to ensure it is set to suspend on lid close, but this makes no difference. Is this a bug or expected behaviour?

Best Answer

Turns out we were all wrong. The magnet which triggers the lid sensor had come away inside the laptop. I confirmed this by holding a fridge magnet up to the camera. As soon as I did that, the laptop suspended fine. So I figured there's a magnet in the base. There was, but it was floating around (clinging to the battery) inside the machine. I put it back in place and it's now working.

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Ubuntu – GNOME: supend on laptop lid close no longer works since 19.10 upgrade

Per investigations at the end of the question, the issue appears to be caused by GDM running a redundant gsd-power process. This can simply be killed as soon as you log in. Here's how I've done it:

Create a kill script as follows:

script=~/bin/kill_gdm_gsd-power.sh
cat > $script << EOF
#!/bin/sh
sudo pkill -u gdm gsd-power
EOF
chmod 755 $script

Your account will need to be allowed to run sudo pkill without a password prompt (make sure you're comfortable with this). Run sudo visudo -f /etc/sudoers.d/NOPASSWD and enter the following
```
Cmnd_Alias PKILL = /usr/bin/pkill
user ALL=(ALL) NOPASSWD: PKILL
```
(replace user above with your own user id)
Open the GNOME startup apps applet (gnome-session-properties) and add an entry with your script, so it runs as soon as you log on.

Ideally we'd find a way to prevent gsd-power from starting up altogether but I found this non-trivial... Please chip in if you find a better way.

A slightly cleaner solution might be to cook a custom handle-lid-switch script per this solution but the script would primarily have to be installed for the gdm user and this may also not be trivial...

There might be some side-effects to killing gdm's gsd-power process, eg: if you log out and leave the laptop to the GDM greeting screen but I think this isn't a scenario many of us will run into.

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Ubuntu – GNOME: supend on laptop lid close no longer works since 19.10 upgrade

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