is probably the most useful variable, since it allows you to find which
variables a driver uses.
+.. envvar:: GALLIUM_GALAHAD <bool> (false)
+
+Controls if the :ref:`galahad` sanity checker module should be used.
+
.. envvar:: GALLIUM_RBUG <bool> (false)
Controls if the :ref:`rbug` should be used.
Wrapper driver. :ref:`rbug` driver used with stand alone rbug-gui.
+.. _galahad:
+
+Galahad
+^^^^^^^
+
+Wrapper driver. Sanity checker for the internal gallium state. Normally
+a driver should n't have to sanity check the input it gets from a state
+tracker. Any wrong state received should be perceived as a state tracker bug.
+
State Trackers
--------------