Comment 62 for bug 1870736

ubuntu 19.10 just upgraded to 20.04 through update-manager.

Just after install and reboot-->black unusable

ctrl+alt+f1 --> login --> black unusable again

ctrl+alt+f3 --> terminal login --> remove nvidia* --> everything ok

normal login --> reinstall nvidia through additional drivers, reboot -->black unusable

ctrl+alt+f3 --> terminal login --> gsettings reset org.gnome.mutter experimental-features --> reboot --> black unusable

reboot--> black unusable--> ctrl+alt+f3 --> terminal login --> remove nvidia-settings--> reboot -->ok: now fractional scaling turning monitor to black for some time and everything goes back to 100% or 200% (depends the start point)

enabling fractional scaling again goes auto 200%-->100% and turn off fractional scaling goes auto back 100%-->200%

BUT with no nvidia-settings there is no extend off screen and there is no freeze on scale changes