The idea: Use a second monitor in Dell XPS L502x with HDMI port in Ubuntu 12.04 The process: I connect the HDMI cable to monitor. I read this and I have video in HDMI monitor with Bumblebee and this commands: optirun nvidia-settings -c :8 DISPLAY=:8.0 firefox I have created a second keyboard/mouse master group with xinput with this solution. The problem: The second monitor (Display 8) doesn't recognize the keyboard/mouse and I cant use it. The question: Do you know some command to attach the keyboard/mouse master group to Display 8? I think that xinput -set-cs may work but it does not.