Egbert Eich has announced this morning on the
RadeonHD mailing list that rotation support has been added to this open-source ATI R500+ driver. This is a feature requested by many to be able to rotate the screen using
RandR with the
xf86-video-radeonhd driver, which is now possible. It is recommended that if you're using the rotation option that you use
EXA acceleration. In addition, the panning mode currently isn't supported when using the rotation support. This support can currently be found in git master and will appear in the next stable release of the RadeonHD driver.