Yesterday evening I’ve encountered an annoying problem. My composite display was broken. My compiz was not working properly. I couldn’t play any games that using 3D texture. I remember that the night before I installed regular updates from Ubuntu. As Homer says, DOUB! That must be the cause. Sometimes I don’t understand why this kind of problem must be happening. When I run “compiz-check”, it returned:

Gathering information about your system…
.
Distribution:          Ubuntu 10.04
Desktop environment:   GNOME
Graphics chip:         nVidia Corporation Device 0a2b (rev a2)
Driver in use:         nvidia
Rendering method:      Nvidia
.
Checking if it’s possible to run Compiz on your system…
.
Checking for texture_from_pixmap…               [ FAIL ]
Checking for non power of two support…          [ FAIL ]
Checking for composite extension…               [ OK ]
Checking for FBConfig…                          [ OK ]
Checking for hardware/setup problems…           [ SKIP ]
.
At least one check had to be skipped:
Error: Unable to detect maximum 3D texture size

I run “nvidia-bug-report.sh” to check what the error is, and then checked the file generated by the script. The file showed that GLX initialization is failed, and recommended me to reinstall the NVidia driver.

(EE) Apr 29 21:46:19 NVIDIA(0): Failed to initialize the GLX module; please check in your X
(EE) Apr 29 21:46:19 NVIDIA(0):     log file that the GLX module has been loaded in your X
(EE) Apr 29 21:46:19 NVIDIA(0):     server, and that the module is the NVIDIA GLX module.  If
(EE) Apr 29 21:46:19 NVIDIA(0):     you continue to encounter problems, Please try
(EE) Apr 29 21:46:19 NVIDIA(0):     reinstalling the NVIDIA driver.

As recommended, I reinstalled the NVidia driver. When reinstalling the driver, the installer returned an error message:

ERROR: File ‘/usr/lib/xorg/modules/extensions/libglx.so’ is not a symbolic link.

After the message, the installer was still continuing the installation process until finish. I restarted my system, and found out that the problem had gone. Then I checked the location of the libglx.so, and it is there. So, I guess that’s the root of the problem. I think Ubuntu has to be more careful with its update, because sometimes it breaks a well-running system. Luckily, the problem is not as complicated as I thought.

Thanks to these forums:

• http://www.nvnews.net/vbulletin/showthread.php?t=117111
• http://ubuntuforums.org/archive/index.php/t-671261.html

And, special thanks to http://forlong.blogage.de/entries/pages/Compiz-Check for the “compiz-check” script. You Rockz!