This is a AI enhanced note on my half day struggle to make my monitor work after KDE transitioned to Wayland
Under Wayland (KWin) the kernel’s DRM/KMS (Direct Rendering Manager/Kernel Mode-Setting) controls display modes. Unlike X11, Wayland does not support on-the-fly modelines via xrandr – it only uses modes that the monitor reports via EDID. In practice, this means you must override the monitor’s EDID to add unsupported modes. This guide shows how to generate a custom EDID for 3440×1440@40Hz on HDMI-A-1 and load it so KDE/Wayland will offer the new mode.
On X11 you could use xrandr --newmode or feed a modeline from cvt/gtf. But on Wayland/KWin, the compositor ignores non-native modes. For example, KWin states “the display is not supported in any geometry other than what is supported by a native mode”. In other words, adding a virtual 40 Hz mode is impossible without changing the E
