I'm running Ubuntu 13.10 on a D54250WYKH. I have a CEC chip attached to it, and through it, I can successfully send CEC commands through the HDMI port (programatically) to my CEC enabled screen (a Samsung UN50F6300AF). However, when I connect to the screen using the DisplayPort++ and a passive DP to HDMI adapter, the CEC chip does not detect the screen and I can't send commands to it. Does anyone have any suggestions or possible reasons why this is? I can supply additional information if necessary.
Thank you for your help.