DVI/VGA/HDI mess on Radeon HD 6570

[Boszormenyi Zoltan <zboszor@pr.hu>]

Hi,

about two months ago I bought a Radeon HD 6570 with
2GB memory for my main computer and I have a single
monitor connected to it, until now via VGA D-Sub.

Last week our secondary TV died (it was 15 years old, R.I.P.)
so I bought a nice 32" LED TV which has 3 external HDMI
connectors.

The HD 6570 has one DVI-D, one HDMI and one VGA connectors
so I thought it would be fun to allow the family to watch videos
while I can also work on the computer.

Here comes my problem: no matter which connectors I use
for the monitor (DVI-D or D-Sub), if the TV is switched on,
HDMI comes up as primary display. The result: GNOME 3
workspaces are switchable on the TV but a single workspace
is visible on my monitor. This would be the perfect setup
if I can reverse the roles of the TV and the monitor.

"man radeon" had an option which I tried but didn't help:
Option "ZaphodHeads" "DVI-0,HDMI-0"

Is there any other option that does what I want?

Thanks in advance,
Zoltán Böszörményi