Power Saving's screen blanking cannot be disabled, even with AC

[Colan Schwartz]

After upgrading to 18.04, whenever I use my laptop's screen (as opposed to an external monitor) and I'm connected to power, the screen goes dark after ~20 seconds even though I have "Dim screen when inactive" off and "Blank screen" set to Never.

I even tried changing the settings listed at https://askubuntu.com/a/1037753/24860 and https://askubuntu.com/questions/1001198/screen-turning-off-when-idle-even-with-power-settings-disabled. Those had no effect either.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: gnome-settings-daemon 3.28.1-0ubuntu1
ProcVersionSignature: Ubuntu 4.15.0-22.24-generic 4.15.17
Uname: Linux 4.15.0-22-generic x86_64
ApportVersion: 2.20.9-0ubuntu7
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Mon May 28 10:24:37 2018
EcryptfsInUse: Yes
ExecutablePath: /usr/lib/gnome-settings-daemon/gsd-power
ProcEnviron:
 LANGUAGE=en_CA:en
 PATH=(custom, user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_CA.UTF-8
 SHELL=/bin/zsh
SourcePackage: gnome-settings-daemon
UpgradeStatus: Upgraded to bionic on 2018-05-19 (8 days ago)

[Launchpad Janitor (janitor)]

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

[Davidian1024 (david-brinovec)]

I believe I've been running into this same bug as well. I've had it with Ubuntu 18.04 and now 20.04 both running as a VM under VirtualBox on Windows 20.

I've been able to configure the settings such that the screen will stay on seemingly indefinitely once logged in.

The issue occurs at the login greeter screen. I've tried changing the settings mentioned above for both the logged in user account and for the gdm user. I've also tried to configure them via /usr/share/gdm/greeter.dconf-defaults

Nothing makes any difference at the login screen. After ~20 minutes the VM's screen goes black and at that point will not come back it just stays black. I am still able to SSH into the VM (which is how I often make use of the vm, though I often do need to access it's GUI.)

If anyone has any idea what could be causing the login screen to blank, I'd really appreciate it. I end up having to restart the VM whenever this happens.