I use (and like very much) Linux, but I use Windows too: in fact, due to work and school reasons, I use Windows more frequently than Linux.
Then I always forget things I used to know about the penguin OS! 🙁
One thing that has been bugging me lately was that, on my freshly installed Gentoo, I could not find a way to enable OpenGL acceleration (or Direct Rendering, as it is called) using Xorg.
The most strange thing of all was that DR worked for the root user but not for my “lowly” common user: I guessed there was some problem with permissions (when is there no problem with perms?) but I could not find the correct tips on the net anymore.
Thanks to a friend of mine (Ciao DisGraz!) I solved the arcanum: I needed to use the DRI section in the xorg.conf file!
By inserting the following piece of code in your xorg.conf file you are effectively changing the permissions on the Direct Rendering Interface device, allowing even common users to gain access to OpenGL acceleration.
I hope this helps you as much as it helped me: I finally can work on my OpenGL project under Linux too!