Im encountering some problems when trying to switch to proprietary nvidia drivers instead of the free drivers. The reason I want to switch drivers is to be able to make use of an external gpu.
After installing the propietary drivers the scaling of what I can try to describe as the system ui ( e.g. Login screen, system settings, taskbar popout, etc… ) seems to change and appear bigger in the screen. Meanwhile other programs such as firefox do not seem affected by it.
I have tried checking the resolution and scaling settings to make sure they are correct and was not able to fix it.
Here is how it looks. Left one is with proprietary drivers and right one with free drivers.
After some trying I was able to determine that the problem lies in the DPI that X server is using. After a lot of unsuccessful attempts at fixing it, I uninstalled nvidia drivers and installed the free ones, which broke my systems as SDDM wouldnt launch. Then from a boot drive I chrooted into my system and deleted the xorg settings and reinstalled the nvidia drivers with
sudo mhwd -i pci video-nvidia-450xx
and somehow once I booted again into linux the dpi was set correctly.
I still have some problems for example my secondary screen ( in this case my laptop screen as I use a external display as primary ) is left with a black background. Windows can still be dragged there, right click works fine, but any panels or taskbar are missing, only displaying black.
Yes, checked that, at the end the problem was with the DPI setting, managed to solve it, dont know how exactly to be honest but seemed that reinstalling from a boot drive did the trick. Still have other problems with the drivers but the scaling/dpi one seems to be fixed for now.
Yeah, the best way to proceed on Manjaro is through MHWD which often requires uninstalling packages before installing drivers and configs.
In Plasma you can set things per monitor when using Nvidia drivers (it works differently on Intel drivers thou), meaning, right-click on the second screen and set wallpaper or effect again. If you want panels, create new ones on the secondary monitor or if you use latte - copy existing ones. Usually they appear on secondary screen automatically (at least my upper panel with global menu and systray did that).
I have hybrid graphics, so I when I use Intel multimonitor setup works flawlessly. When I switch to Nvidia or hybrid mode, various problems start. Since I use laptop and I only occasionally plug in the secondary screen, things are unstable on Nvida and hybrid mode and settings are not remembered, or plasmashell crashes, or things work, but not quite - so plasmashell is somehow corrupted. So what I usually do: I kill plasmashell (in sysguard) and launch it again through krunner. Usually this fixes things and I can set secondary monitor. Sometimes it needs more plasmashell restart attempts.
Maybe if I used multimonitor setup all the time things will behave well, but since I plug it off and on only sporadically, in meantime there are some updates (xorg, drivers, kernels, systemd) that may mess with the saved setting? Generally, many weird things are happening on Nvidia drivers. Maybe you find some workarounds or solutions.