I thought that Xinerama is depreciated after moving everything to RandR.
Phoronix: DMX2 Bits For X.Org Server To Move Forward
Back in 2008, Novell's David Reveman published his own branch of the Distributed Multi-head X (DMX) server which he called dmx-2 as it was close to a complete rewrite of the original DMX implementation. David's DMX-2 branch was less complex but provided a greater set of features, including X-Video, RandR 1.2, and Composite support in a DMX environment, D-Bus configuration, and many other changes...
http://www.phoronix.com/vr.php?view=Nzg2NA
I thought that Xinerama is depreciated after moving everything to RandR.