Can't connect third display (TV) in 12.04 beta
I have a setup with three displays:
- My primary 1920 x 1080 monitor, connected through DVI
- My secondary 1680 x 1050 monitor, connected through DVI
- My 1920 x 1080, connected through HDMI
They're connected to an AMD HD6970. Because I'm not using a DisplayPort connection it is not possible to use all three displays at the same time due to a hardware limitation. That is not a problem for me though, as I am only interested in either working (primary + secondary monitor) or watching movies / TV-shows (primary monitor + TV) and thus only need two monitors active at the same time.
After installing 12.04 last week I was able to setup my work configuration just fine. When I plug in the TV though, the OS seems to think it is a good idea to use all three monitors at the same time. As mentioned before this isn't actually possible, so everything just turns black. I can switch to a different TTY and reboot, but the only way to get an image again is to unplug at least one of the monitors. I tried copying over my old 11.10 xorg.conf from when I had just the two monitors working (with the TV connected but unused), to no avail.
I have long given up on finding a way of switching between my two setups without hours of trial and error, and I was previously content using just my work setup in Ubuntu and booting to Windows when I want to watch movies (pretty much the only thing I still use Windows for these days). As of 12.04 I'm required to crawl behind my desk and unplug the HDMI cable every time I boot back to Ubuntu, which is obviously very inconvenient.
I am using the latest proprietary drivers from the AMD website, which I installed manually (the automatic setup crashed, a different problem for which the bug reporter redirected me to an existing issue). I initially had the same problem with the open source drivers though.
Can you help with this problem?
Provide an answer of your own, or ask Elte Hupkes for more information if necessary.