Solved. It was a problem with package libgl1-mesa-swx11. Removing it, the OpenGL rendered went back to the Mesa DRI for 965GM card....
Running glxinfo | grep render was returning "OpenGL renderer string: Mesa X11" and removing the libgl1-mesa-swx11 package the same command returns "OpenGL renderer string: Mesa DRI Intel(R) 965GM GEM 20090712 2009Q2 RC3" and everything works fine now.
Solved. It was a problem with package libgl1-mesa-swx11. Removing it, the OpenGL rendered went back to the Mesa DRI for 965GM card....
Running glxinfo | grep render was returning "OpenGL renderer string: Mesa X11" and removing the libgl1-mesa-swx11 package the same command returns "OpenGL renderer string: Mesa DRI Intel(R) 965GM GEM 20090712 2009Q2 RC3" and everything works fine now.