KDE Plasma blurry on second monitor

the kernel will not break anything, and you will still have the 5.15 kernel … so just dont even waste your time with the test installation … go to system settings/kernel and install the 5,18, reboot and select it in the grub menu advanced options, thats it…
from your output above you are using xorg not wayland:

Display: x11 server
The following packages will be installed:

linux518

linux518-nvidia

Starting

resolving dependencies...

looking for conflicting packages...

Packages (2) linux518-5.18.14-1 linux518-nvidia-515.57-10

Total Download Size: 38.44 MiB

Total Installed Size: 172.85 MiB

:: Proceed with installation? [Y/n]

:: Retrieving packages...

linux518-nvidia-515.57-10-x86_64 downloading...

Errors occurred, no packages were upgraded.

error: failed retrieving file 'linux518-nvidia-515.57-10-x86_64.pkg.tar.zst' from mirrors.fossho.st : The requested URL returned error: 404

error: failed retrieving file 'linux518-nvidia-515.57-10-x86_64.pkg.tar.zst.sig' from mirrors.manjaro.org : The requested URL returned error: 404

warning: failed to retrieve some files

error: failed to commit transaction (failed to retrieve some files)

I will try on the test installation.

So, it’s x11… I thought maybe manjaro-kde is just using wayland and manjaro-xfce still doesn’t. But ok.

refresh your mirrors, you will not be able to install anything otherwise …
sudo pacman-mirrors --fasttrack 5
then install kernel

The mirror update didn’t solve this. Still the same error.

But I installed 5.18 on the test-system. No changes, still blur.

I just installed 5.19-rt too now, on the main system (a pacman -Syu solved the error above). But still blurry.

post output from:
cat /etc/X11/mhwd.d/nvidia.conf

cat /etc/X11/mhwd.d/nvidia.conf
# nvidia-xconfig: X configuration file generated by nvidia-xconfig
# nvidia-xconfig:  version 515.57

Section "ServerLayout"
    Identifier     "Layout0"
    Screen      0  "Screen0"
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
EndSection

Section "Files"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Mouse0"
    Driver         "mouse"
    Option         "Protocol" "auto"
    Option         "Device" "/dev/psaux"
    Option         "Emulate3Buttons" "no"
    Option         "ZAxisMapping" "4 5"
EndSection

Section "InputDevice"
    # generated from default
    Identifier     "Keyboard0"
    Driver         "kbd"
EndSection

Section "Monitor"
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "Unknown"
    Option         "DPMS"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
        Option "NoLogo" "1"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
    Monitor        "Monitor0"
    DefaultDepth    24
    SubSection     "Display"
        Depth       24
    EndSubSection
EndSection

Section "Extensions"
    Option         "COMPOSITE" "Enable"
EndSection

 
Section "InputClass"
    Identifier          "Keyboard Defaults"
    MatchIsKeyboard        "yes"
    Option              "XkbOptions" "terminate:ctrl_alt_bksp"
EndSection

and if you open nvidia settings, and check there for settings - triple buffer/ pipeline …

I didn’t find these settings (tripple buffer or pipeline), but what I found out in the nvidia settings, it seems to be the Hz settings of my second monitor, that is automatically set too low. When I switch it manually to 60 Hz it’s much clearer.
But if then I switch screens it’s again set on “auto” so I have to adjust it manually. And if I click on “save to X Configuration file” in the nvidia settings, it tries to write into /etc/X11/xorg.conf and I get the message “unable to open…” And indeed there is no such file.

So the question is, where do I save such settings as a profile?

I again switched screen off and on, blur is back, and I took a look in the nvidia settings. Both monitors are listed with 60 Hz frequency. So maybe there is something else, that happens, when I set the 60 Hz manually and hit the apply button. I don’t know.

and under system settings/display configuration whats the refresh rate

It’s 60 Hz.

I found some composit pipeline settings in advanced mode yet (one is force full pipeline). I tried both, but no success.

in nvidia settings search for FXAA and if its enabled, disable it, then reboot

No, it’s disabled.

so its unchecked? enable again the force pipeline and reboot

No, same problem. Maybe worth. I didn’t had to switch screens to get the blur back, but only to start the nvidia setting-window and move it a little.

And although I see, that in the nvidia settings, the force full pipeline option is unchecked again. So, it doesn’t seem to save anything.

so edit the section part of the nvidia.conf: kate /etc/X11/mhwd.d/nvidia.conf

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
        Option "NoLogo" "1"
EndSection

to look like this:

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    VendorName     "NVIDIA Corporation"
    Option  "ConnectToAcpid"    "Off"
    Option "metamodes" "nvidia-auto-select +0+0 {ForceFullCompositionPipeline=On}"
EndSection

save it, and reboot

No change.

I have also tried to save the nvidia-settings changes. I could click on preview before it tried to save it to the non-existing xorg.conf. So I copied all into the nvidia.conf, but this was much worther. So I copied the original content back to the nvidia.conf.