I am not familiar with code, so I just test what I could see... hope it helps (I posted also on bug 1873403, if not necessary I'll remove it. No intention to spam).
------------not live: tests as I remember: without nvidia 100-->ok 125,150 too slow with nvidia 100--> too small 200-->too big enable fractional scaling 125-->200 150-->200 175 -->black (stop/start freesync from monitor, restored - maybe random behavior) 2nd try 100-->ok 125-->black (couldn't restore it, ctrl+alt+f1 & login = black again) unistall nvidia tested drivers, try nouveau after two changes, I could see ubuntu desktop became small or big inside my screen and around it I cound draw with the window I was holding with the mouse. If I put it inside ubuntu desktop area of my screen it works fine, outside (right column and down line) it just performs like windows xp windows when it stuck (never saw it again on ubuntu since 11.10 that I am using it). ------------live: test and keep these notes: install nvidia again reboot - 3rd try 100--> bigger desktop than my screen, needs to scroll (down or right) to see the rest 200--> the same enable fractional scaling (returns to 100 by itself) 150-->black (stop/start freesync from monitor, restored - maybe random behavior) 100 --> enable fractional-->200 by itself I repeat it, doesn't happen the second time 150-->black remove nvidia* through synaptic reboot 100-->ok 125,150,175 too slow 200-->ok install nvidia tested 100-->οκ 200-->οκ enable fractional scale-->turn to 100 itself 150-->black 125-->200 125(200) change back to 100 first 175-->black 200-->ok on 200, close fractional scale-->instead of return to 100 itself it doubles the area of the desktop (bigger than my real monitor area, so I have to scroll to see the rest of the desktop) 100-->100 with the same large desktop area issue deactivate fractional scale-->issue remain logout,logon--> 100 & ok -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to mutter in Ubuntu. https://bugs.launchpad.net/bugs/1870736 Title: [nvidia] Screen scaling 125% gives 200% Status in gnome-control-center package in Ubuntu: Confirmed Status in gnome-shell package in Ubuntu: Confirmed Status in mutter package in Ubuntu: Confirmed Status in nvidia-graphics-drivers package in Ubuntu: Confirmed Bug description: Procedure used: 1. Fully updated system via apt update && apt upgrade 2. Select the screen setup in gnome control center 3. Click the "Fractional scaling" toggle 4. Select 125% and click the green "use" button top right (it says "Anvend" in dansih) 5. Observe that the window has grown a lot, click the "use new settings" button 6. The window tells me, I am at 200% scaling. The "200%" option is now highlighted. 7. Switch back to 100% and file this bug. ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: ubuntu-release-upgrader-core 1:20.04.16 ProcVersionSignature: Ubuntu 5.4.0-21.25-generic 5.4.27 Uname: Linux 5.4.0-21-generic x86_64 NonfreeKernelModules: nvidia_modeset nvidia ApportVersion: 2.20.11-0ubuntu22 Architecture: amd64 CrashDB: ubuntu CurrentDesktop: ubuntu:GNOME Date: Sat Apr 4 09:42:34 2020 InstallationDate: Installed on 2018-01-14 (810 days ago) InstallationMedia: Ubuntu 16.04.3 LTS "Xenial Xerus" - Release amd64 (20170801) PackageArchitecture: all ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=da_DK.UTF-8 SHELL=/bin/bash SourcePackage: ubuntu-release-upgrader Symptom: release-upgrade UpgradeStatus: Upgraded to focal on 2020-04-03 (0 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-control-center/+bug/1870736/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
