Monitor not seeing full native resolution in KDE

Source: bbs.archlinux.org --- Thursday, August 31, 2017
Also relevant, I am trying to achieve this resolution over HDMI. This monitor does deliver native resolution to a Windows machine over HDMI, but in linux, the maximum achieved resolution is 1080p. If it is connected via DisplayPort, it delivers 1440p in Linux, but in my day to day configuration, the DisplayPort connector for this monitor will not be available to the Linux machine. ...

from Windows http://ift.tt/2x9M4ff