https://bugs.freedesktop.org/show_bug.cgi?id=110214
--- Comment #62 from Diego Viola diego.viola@gmail.com --- We found quite a few things during our research:
export MESA_EXTENSION_OVERRIDE="-GL_NV_texture_barrier"
This helps alleviate the problem (xterm does not have the issue with this), however, the problem is still present in Xephyr.
We tested Xephyr from the current git master down to Xephyr from xserver 1.16 and the problem is also present, however, setting the following environment variable:
export R600_DEBUG=nodpbb
Makes the issue disappear entirely.