My computer has an HDMI output, so I want to use my HD TV as a second monitor. This works but I cannot exploit the full 1080x1920 resolution because the maximum virtual screen size is 1600x1600. The main display on my laptop is 768x1366, so I can just squeeze in the TV as a second monitor if I use it at the same resolution, but I would really like to have both displays at full resolution, which would require a maximum virtual screen size of 1920 horizontal by 1848 vertical. I have read through the xorg configuration documentation but I am baffled as to what I actually have to do. I cannot see anywhere in the existing configuration files where the current maximum screen size is set.