OpenSolaris doesn't use an xorg.conf unless you specifically create one by hand. You should make it /etc/X11/xorg.conf if you want it to be used by Xorg. You will also notice a file /etc/X11/.xorg.conf which is apparently used to give the X startup script a helping hand at configuring things automagically.
Cheers Andrew. -- This message posted from opensolaris.org
