KDE Plasma on wayland: issue with ultrawide screen (21:9)

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1

The configuration was working few days ago, but now, I unable to use normal 2560x1080x75hz definition (using laptop with hybrid nvidia/intel card RTX2060)

mhwd -li
> Installed PCI configs:
--------------------------------------------------------------------------------
                  NAME               VERSION          FREEDRIVER           TYPE
--------------------------------------------------------------------------------
     video-modesetting            2020.01.13                true            PCI
video-hybrid-intel-nvidia-prime   2025.09.29               false            PCI

When searching which output is in use with xrandr

Screen 0: minimum 16 x 16, current 3840 x 1080, maximum 32767 x 32767
eDP-1 connected primary 1920x1080+1920+0 (normal left inverted right x axis y axis) 382mm x 215mm
   1920x1080    143.88*+
   1440x1080    143.90  
   ...
   720x400      143.88  
   640x350      143.57  
HDMI-A-1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 798mm x 334mm
   1920x1080     59.96*+
   1440x1080     59.99

and if I try to change connexion (external USB-C/HDMi interface)

eDP-1 connected primary 1920x1080+1920+0 (normal left inverted right x axis y axis) 382mm x 215mm
   1920x1080    143.88*+
   1440x1080    143.90  
   ...
   720x400      143.88  
   640x350      143.57  
DP-1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 798mm x 334mm
   1920x1080     59.96*+
   1440x1080     59.99  
   1400x1050     59.98

So HDMI-A-1 or DP-1 are same LG monitor with 2560x1080 capacity.

How could I troubleshoot that without AI help (or risks, it depends on my luck) ?

2

… does not work with Wayland. You have to use kscreen-doctor — it’s in the repository.

1 Like
3

I should also add that, from Plasma 6.6.0, users will be able to add custom screen modes, including custom resolutions:

Plasma 6.6.0

Massively improved support for screen mirroring in the Wayland session. Now it works really well! (Xaver Hugl, bug #481222 and kscreen MR #439)

You can now use the kscreen-doctor tool to add custom screen modes, useful for supporting exotic or misbehaving screens in the Wayland session. (Xaver Hugl, bug #456697)

Russell Haley 2025-05-08 16:25:34 UTC

(In reply to Roke Julian Lockhart Beedell from comment #12)
(In reply to Russell Haley from comment #0) >

Although the original FR’s description focusses upon a custom refresh rate/frequency, would this also encompass applying a custom resolution? It appears to, based upon the example commands provided, but an explicit confirmation would be useful. (Otherwise, a pointer to the relevant FR would be even more so. :white_heart:)

Yes, see that Bug 472321 “[WISHLIST] Add custom resolution support.” was marked duplicate of this one.

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4

@Aragorn and @scotty65 You saved my night :slightly_smiling_face:

#Tested and approved
kscreen-doctor output.DP-1.mode.2560x1080@75

#Will be tested in few hours
kscreen-doctor output.HDMI-A-1.mode.2560x1080@75

Thanks

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