I'm running Ubuntu 12.04 LTS on a Dell XPS L502X and when I connect the HDMI cable from the TV to the computer Ubuntu detects nothing at all, It works perfectly fine in Windows 7 though. I've already went to the Display control, plugged and unplugged the TV, clicked the Detect Displays button, and nothing. Do I have to activate the HDMI output or something? Because I used another computer with a VGA output and it worked perfectly.