Thank you SGI, for freeing the GNU/Linux 3D desktop!
In January of 2008, software code at the heart of GNU/Linux 3D applications was discovered to be non-free—a potential disaster for free software advocates hoping to see advanced graphical acceleration now common on modern operating systems.
The code, licensed by Silicon Graphics (SGI), was distributed under the SGI Free License B and the GLX Public License. These licenses, although permissive, contained three sets of terms which created significant burdens for all users and developers and a particular problem for the free software community because they made the code non-free (see the Free Software Definition at http://www.gnu.org/philosophy/free-sw.html).
The Free Software Foundation (FSF) Free Software Compliance Lab's Brett Smith explained, "We discovered that these licenses covered contributions that SGI had made to the X.Org Project and the Mesa 3D Graphics Library. These projects, including SGI's code, are an important and familiar part of modern GNU/Linux desktop systems. The FSF Compliance Lab then worked with SGI towards today's announcement."
You can read SGI's press release here: http://www.sgi.com/company_info/newsroom/press_releases/2008/september/opengl.html