In all honesty, this failure is more of an Xorg issue than a steam linux issue. My suggestion is to create a thread on the ubuntu forms and attach the /var/log/Xorg.0.log along with a diff -u between the original and new xorg.conf.
By default xorg.conf, I assume you mean the one created or updated by nvidia-settings.
If you decide to create a new thread you are welcome to drop a link here and I'll help any way I can.
Hello @GitRASQ, are you still experiencing this issue on an up to date system?
I've been using Arch for a long time and have different hardware now. This certainly isn't a problem for me anymore.
Nothing extracted yet.
I installed steam and it worked fine at first. Then I created an xorg.conf file to fix a text scaling issue with the Nvidia drivers. After a reboot I tried to start steam and got the error message: "OpenGL GLX extension not supported by display".
Removed xorg.conf, rebooted and it works again. Replaced xorg.conf with default version to check whether the problem was caused by the line I added, but got the same error with default file. Steam won't start as long as the file exists.
Kubuntu 14.04
Nvidia GTX 560
Driver 331.38