Black screen when starting xfce4. X works.

[Yttrium]

Hi,

if I start xfce4 with "startxfce4" or with "startx" while .xinitrc contains "exec startxfce4" I just get a black screen without a cursor. The system isn't frozen, I can switch ttys and quit xfce4 with CTRL+C from the tty which it was started from.

The X-server is working, I can enter startx (empty .xinitrc) and run xfdesktop xfce4-panel xfce4-settings-manager etc. from within this minimal X environment.

It's a fresh installation (no special hardware or settings) and as described before, X works fine (else I couldn't start the xfce4 desktop from the terminal).

I am using a minimal xorg.conf which was created by aticonfig. It looks exactly the same like the one on a different partition on the same computer which has a working KDE installed. Xorg.0.log also seems fine.

Any ideas? Of course I'll provide any further information if needed. I don't know how to debug this problem as there are no error messages and everything seems like it's working fine, but obviously not as expected.

Another problem that might have the same cause is when I try to start my kernel with the kernel commandline option vga=791 (for example) my screen just stays black.

Help would be much appreciated.

P.S. My Xorg.0.log: http://pastebin.com/xWNv5WNZ
_________________
LILA - Live Iptables Log Analyzer