Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
Minutes after the release of the RadeonHD v0.0.3 driver, the initial-randr branch for x86-video-radeonhd was merged into master. What this means is that you no longer need to checkout this separate branch but that all of the RandR 1.2 support is now in the mainline code for this open-source driver.
The RadeonHD driver provides full RandR 1.2 support and even some initial work for RandR 1.3.