I have my computer next to my hdtv. The main screen is connected via DVI while the tv is connected via HDMI.
If I start the computer without the HDMI plugged in, everything is ok: I see the login screen and sound is output through analog out.
But if the HDMI is plugged in before I start the computer, only the tv gets an image (the login screen), the main screen is black or at some times purple, but even after login the main screen is black. Also sound is still output through analog out.
Not sure whether it's a hw issue, or an Ubuntu issue, or a combined hardware/Ubuntu compatibility issue (Sandy Bridge).
This is my setup:
- Ubuntu 11.10 Oneiric Ocelot (64bit)
- ASUS P8H67-M LE
- Intel Core i3-2100
I don't have any custom video settings, my main screen is recognized properly when HDMI is not plugged in at startup.