https://bugs.freedesktop.org/show_bug.cgi?id=59322
--- Comment #7 from Marek Olšák maraeo@gmail.com --- Yes, the GALLIUM_MSAA environment variable might break some apps, because it changes the default framebufer to MSAA, which adds lots of limitations to BlitFramebuffer. For example, you can no longer use BlitFramebuffer to do a stretched blit, because the ARB_fbo specification doesn't allow it if either src or dst is multisample, etc.
That's why GALLIUM_MSAA should be used carefully.