X11 - Wayland - Dual monitors issue

Hey all!

I recently got a new monitor, unfortunately I’m facing to a little issue with Kubuntu.

When I’m using X11, I’m getting a resolution issue :

I tried different things like changing the resolution, refresh rate, switching the cables etc.

After searching a bit, I found a thread where someone pointed that the issue could be related to X11.

I switched to Wayland, and miracle it’s working fine! But the OS is a bit laggy (trail on my cursor, pretty slow to open start menu etc.)

Any ideas on how I could fix this resolution issue with X11 or the lags with Wayland ?

If you’re using any scaling, then it’s not easily fixable on X11; mixed-DPI multi-screen setups aren’t supported and don’t work well in Plasma on X11. However if you’re running them both at their native resolutions and 100% scale, then there’s probably a bug in our code somewhere. I do see that you’re using Plasma 5.24, so there’s a chance any such bug was already fixed in the big multi-screen overhaul in Plasma 5.27, which you can get by upgrading to Kubuntu 23.04. In general I don’t recommend sticking to Kubuntu’s LTS releases.

But still, I’d recommend using Wayland if you have more than one screen. The multi-screen experience is much better overall. If you’re using an Intel iGPU, the performance issue you’re seeing is might be fixed with Plasma 5.27.7. If not, please do submit a bug report so we can investigate and fix it! …But only after upgrading to 5.27. :slight_smile:

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Hey Ngraham,

Thanks a lot for your quick reply!

  • I was using the native resolution with X11
  • And my GPU is a Nvidia 30xx

Good news, after a reboot the system is now working fine with Wayland, it’s not laggy anymore. (I’m pretty sure I already rebooted)

If the issue re-happen, I will upgrade Plasma to 5.27 :slight_smile: