I'm using CachyOS with KDE Plasma on Wayland and an Intel UHD integrated GPU. My laptop's built-in display supports 60 Hz and 144 Hz, but I'd prefer to use 120 Hz without switching between those modes. I created a custom 120 Hz resolution successfully on Windows, but I haven't been able to make the equivalent override work on Linux. Attempts with Linux display tools did not work under Wayland, and one Xorg attempt caused problems. Is there a reliable way to add or select a 120 Hz mode?
2 Answers
First check Plasma’s System Settings under Display and Monitor. If 120 Hz is exposed by the panel’s EDID, it should appear in the refresh-rate menu and can be selected directly. If it isn’t listed, Linux may not be receiving that mode from the display firmware.
Custom display modes are much more limited on Wayland than on Xorg. Tools such as xrandr are intended for X11 and generally won’t add a custom mode to a Wayland session. Plasma’s Wayland support normally relies on the modes reported by the monitor, so a 120 Hz option may require a kernel or driver-level override rather than a desktop setting.
Since the panel is already confirmed to run at 120 Hz on Windows, checking the EDID reported by Linux would be a useful next step. If the mode is missing there, the issue is likely how the firmware or graphics driver exposes the panel modes, not the Plasma settings themselves.