I'm not too sure about sparc hardware, as I don't know which graphic server it uses, but on my system(x86) the same thing happened. What I had to do was make an xorg.conf as the install doesn't create one.
On the CLI execute '/usr/X11/bin/xorgconfig' and this should step you through creating an xorg.conf file- as long as you are using the Xorg server of course.
or
execute '/usr/X11/bin/Xorg -configure' this should create a basic xorg.conf and you just edit it yourself where appropriate.
Personally, if you know your graphic board,monitor, keybrd and mouse along with refresh rates the first method is probably best.
H.T.H.
the 'm464config' and other ...configs are
commands. They live in /usr/sbin, so as
the root user you should be able to run them
without qualification.
# m64config -res 1024x768x75 try
Is an example of setting the res to 1024x768 at
75hz for a trial period.
In general, a reboot is required to get the new
setting to take effect correctly.