Radeon X300, dual head

[Hans J. Koch]

Hi,
I used to have a working system with a Radeon X300 (RV370) card and two
monitors 1680x1050 each. I used an ancient xorg version (something like
6.8, can't recall) and had a MergedFB+Xinerama configuration. Worked well
for me.

A few days ago I dist-upgraded my Debian sid which brought me version
7.3 of xserver-xorg. Since that I'm trying to get my dual head setup
working again...

I understand that MergedFB has been replaced by RandR 1.2 extensions.
Sounds like a good concept to me, but unfortunately it doesn't work here.

X correctly detects my hardware, but no matter what I do, I always have
the same output on DVI-0 and VGA-0. I googled around and found a lot of
pages describing how to setup xorg.conf, and I think it's OK.

Question: Is this supposed to work or a known problem? What do I have
to do to get a working dual head setup again?

Thanks,
Hans