Can Xinerama be completely disabled in Gutsy?

[Dan Munckton]

Hi

I'm trying to find a workaround for the following Java problem:

#154613: Xinerama prevents Java fullscreen exclusive mode in Gutsy
[https://bugs.launchpad.net/ubuntu/+source/sun-java6/+bug/154613]

Java uses Xrandr to achieve its Fullscreen Exclusive Mode, but rightly
avoids using it if Xinerama is in use. So Java Fullscreen Mode is only
possible when Xinerama is not reported present in the running Xorg.

In both Feisty and Gutsy Xinerama appears to be built-in. In Feisty
Xinerama isn't reported as present/active (using XQueryExtension() etc),
in Gutsy it is.

So as a workaround I need to find a way to completely deactivate and
disable Xinerama in Gutsy.

In the xorg.conf manpage it indicates that adding the following option
in the "ServerFlags" section should disable it, but it's not.

Section "ServerFlags"
  Option "Xinerama" "off"
EndSection

After restarting X I check in /var/log/Xorg.0.log and find the option is
recognised/parsed but still when I test Java and also query Xorg
directly using the Xlib API it still shows as present.

So I have the following questions:

1) What is the major difference between the way Xinerama is included in
Gutsy in comparison with Feisty?

2) Is it going to be possible to disable Xinerama from within xorg.conf?

3) If I disable Xinerama what am I likely to break (e.g.
DisplayConfigGTK)?

4) Is there another way to achieve this?

I am quite happy plugging away at this on my own but if anyone with more
Ubuntu/Xorg knowledge can give me some insight at this stage it would be
much appreciated.

Cheers

Dan