When I try to use DGA2, the screen goes black and the PC completely halts!
When I try
to use DGA2, the screen
goes black and
the PC completely halts!
You are probably using a XFree86 server with a very buggy DGA2
implementation, such as 4.0.3 (shipped with Red Hat 7.1 for example).
Upgrading to 4.1.0 will probably solve your problem. You can obtain
it from ftp://ftp.xfree86.org/pub/XFree86/4.1.0/binaries/
the directory suited to your platform and following the instructions
you find in the Install file.