http://gitweb.freedesktop.org/?p=xorg/d
However I've never been happy with many parts of that code as it still relies on the old radeon system of having 2 CRTCs mapped to 2 outputs and this isn't really suitable for a flexible randr driver, however it is also less likely to regress heavily..
With this in mind I started to go a different direction and started the randr-1.2-tng branch in my personal ATI repository,
http://gitweb.freedesktop.org/?p=us
This removes the whole idea of only having two outputs and tries to allocate an output per type of output (so Analog, Digital, LFP, TV), and assigning those to a connector.. I need to do DDC optimisation so DVI connectors (which have Analog and Digital outputs on them) only do DDC once...