What does the XFree86 DRI extension?
The XFree86-DRI X server extension is basically used for communication between the other DRI components (the X server, the kernel module, libGL.so and the 3D DRI drivers).
The XFree86-DRI module maintains DRI-specific data structures related to screens, windows, and rendering contexts. When the user moves a window, for example, the other DRI components need to be informed so that rendering appears in the right place.
Where does the XFree86 DRI extension resides?
The DRI extension module usually resides at /usr/X``11R6/lib/modules/extensions/libdri.a.
The DRI extension source code resides at xc/programs/Xserver/GL/dri/ .