I'm updated fully as of today under 20.04 and have the same issue described in OP with an NVIDIA M2000M in a Thinkpad P50 using the proprietary drivers and 1 1080p monitor (the laptop panel) and 1 4k monitor (Dell external).
#83 indicated that they changed things so that their PRIME settings were "on demand" and that made things work for them, but my external monitor just quits working when I change it to that. Things work mostly as expected with the nouveau driver, but no scaling really works under the proprietary driver. I would use the nouveau driver but it seems very sluggish under any scaling factor. That said, my issue isn't really about fractional scaling, FWIW. I want to set the external display at 200% and set the internal one at 100%, a configuration which doesn't require fractional. But doing this produces 200% on both panels reliably (and the percentage values in settings reflect that both are set to 200%) under the proprietary drivers. So right now I can effectively either choose from these three options: a) use nouveau, make both displays work as I would like, but have a very sluggish UI experience b) use proprietary and have text that's too small to read for my old eyes on the 4K external monitor but have a usable built-in display, or b) use proprietary to get reasonably sized text and icons on the 4K external monitor but accept that the built-in monitor is not very useful because its effective resolution is 960x540. It seems that some people have gotten the combination of proprietary NVIDIA drivers and scaling to work. I would try this on another system to doublecheck but I don't have a machine handy with NVIDIA graphics different than the one in my system (M2000M). -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-control-center 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 mutter 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