[Xorg] xcompmgr

Joe L. anuril at hotmail.com
Fri Jul 16 09:22:35 PDT 2004

I've been trying to get xcompmgr to start up, but it seems that it can't 
figure out how to interface the fixes, damage or composite extensions.

>From the Xserver compile HOWTO on freedesktop.org, it seems as though the 
extensions don't require a line in /etc/X11/xorg.conf as certain other 
modules do.  If it does, the option is hidden pretty well -- I've been 
googling for hours for examples of xorg.conf files that load damage or 
composite extensions.  I also tried lines similar to:
        Load "damage", and
        Load "Xdamage"
in hopes of hitting something by accident.  Of course, these desperate 
guesses never garnished any favorable results.  I'm pretty convinced at this 
point that xcompmgr isn't looking for an extension that one would expect to 
show up in xdpyinfo's output.  So I took a look at xcompmgr's source and 
followed the X*QueryExtension functions back to the source for libXrender 
and libXcomposite.  The X*HasExtension macro ended up checking a `codes' 
variable that is initialized via XInitExtension (in the case that the 
X*ExtInfo checked doesn't have an entry for the current display in its list) 
which ends up being exported in the libX11.so.6.  Knowing that 
XInitExtension is exported by the core X11 library leads me to believe that 
the libXcomposite/libXdamage/libXfixes (although I didn't check the code for 
damage and fixes) are the usual extensions that could (/should) be included 
via a Load directive in the Modules section of /etc/X11/xorg.conf.  The idea 
of a load directive is, unfortunately, contradicted by the fact that the 
sample xorg.conf file included via CVS contains no such Load statements -- 
and supposedly should work (i.e.: the XserverInstallGuide).

OTOH, the FD.o XserverInstallGuide exported LD_LIBRARY_PATH.  I imagined 
xcompmgr may be trying to load these modules in at runtime.  That ended up 
failing as well:

%strings /usr/local/bin/xcompmgr | grep libXdamage
%strings /usr/local/bin/xcompmgr | grep libXcomposite
%strings /usr/local/bin/xcompmgr | grep libXfixes
%ll /usr/X11R6/lib/libXdamage.so.1
-rwxr-xr-x  1 root  wheel  9098 Jul  6 05:37 /usr/X11R6/lib/libXdamage.so.1*
%ll /usr/X11R6/lib/libXcomposite.so.1
-rwxr-xr-x  1 root  wheel  8907 Jul  6 05:35 
%ll /usr/X11R6/lib/libXfixes.so.1
-rwxr-xr-x  1 root  wheel  18575 Jul  6 05:35 /usr/X11R6/lib/libXfixes.so.1*
%setenv LD_LIBRARY_PATH /usr/X11R6/lib
No composite extension

Can anyone point me to some docs on getting these extensions loaded?

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