To add some context the feature that I am asking for is working DRI3
+
present ... with mesa 10.2
it gives us GLX_EXT_buffer_age which finally fixes tearing issues in
mutter that some user are experiencing
without using workarounds like forcing the compositor to always redraw
the whole screen (which costs performance
and battery life).
There is no working DRI3 + present anywhere at all yet, or if there is
it involves SNA which has its own set of not working.
Dave.