https://bugs.freedesktop.org/show_bug.cgi?id=110214
--- Comment #74 from Diego Viola diego.viola@gmail.com --- (In reply to Diego Viola from comment #65)
Just to make it a bit more clear:
If I set that environment variable while I'm already on X:
export MESA_EXTENSION_OVERRIDE="-GL_NV_texture_barrier"
It has no effect on Xephyr (from current git master), i.e. xterm still shows the bug.
This comment is completely wrong, ignore it.