Set permanent custom resolution for Ubuntu and KDE Using Xrandr and Xsetup
After switching from Gnome and Unity to KDE, I had a problem with SDDM and it was that it could not detect correct resolution for my UltraWide monitor and set it to Full HD instead of 2560×1080. I had a similar problem in Ubuntu with another old monitor. Anyway that solution is same in both cases. The solution for this problem is using Xrandr and Xsetup to set the correct resolution and make it permanent. ...