http://bugs.winehq.org/show_bug.cgi?id=29732
--- Comment #8 from Jeremy Huddleston jeremyhu@freedesktop.org 2012-01-31 12:28:40 CST --- The warning should say Xi2 is not *enabled* rather than not supported. The server supports Xi2, but wine claims that it doesn't. The warning should be less ambiguous.
What do you mean by, "..., though it will still work better if you install XInput2" ... Xi2 is enabled in the server, but you leave it set as xi_unknown inenable_xinput2