commit 406478dc upstream.

Fixes rendering failures in Unigine Tropics and Sanctuary and the mesa
"fire" demo.
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>