SUMMARY

In some applications, the correct display resolution is not recognized. As a result, some of the applications cannot be started. The problem has existed since Plasma 6. Under Plasma 5, this problem did not occur.

Two examples:

1.
Starting Kodi Wayland, the native display resolution is not recognized (only 1829x1029p and 3658x2058p available). If kodi --windowing=x11 is started, all available resolutions are detected correctly (...,1920x1080,2560x1440).

2.
Starting a native Linux game (e.g. SDL based) on the dedicated GPU, the following error message occurs:

X Error of failed request:  BadAlloc (insufficient resources for operation)
  Major opcode of failed request:  147 ()
  Minor opcode of failed request:  7
  Serial number of failed request:  117
  Current serial number in output stream:  118
Monitored process exited.

---> RANDR issue.

When starting Wine/Proton games, no problems occur at all.

----

With theseus-ship, the resolution in Kodi Wayland was correctly recognized again.

To fix the problem with native Linux games, I tested replacing SDL2 with SDL3 / SDL2-Compat. At least, the error message major opcode... did not appear again.

Both problems did not occur under Plasma 5.


SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Artix Linux x86_64, Linux 6.10.0-zen1-1-zen

(available in About System)
KDE Plasma Version: KDE Plasma 6.1.3
KDE Frameworks Version: 6.4.0
Qt Version: 6.7.2


ADDITIONAL INFORMATION

Under Kscreen, the Legacy applications (X11) setting is set to Apply scaling themselves. If the setting is set to Scaled by the system, the resolution will not be recognized in Wine/Proton games either, presumably also in other applications (global). Resolution set in kscreen: 2560x1440p. Refresh Rate: 240 Hz.