When I delete the /usr/lib/dri/r600_dri.so file from the stock Alpha-5 libgl1-mesa-dri package (7.6.0~git20090817.7c422387-0ubuntu3) then X will start up correctly with DRI enabled using both the Radeon and Radeon HD drivers.
AIGLX reverts to software rendering as expected.
Acer Aspire 5536 with a Radeon HD 3200 card.
When I delete the /usr/lib/ dri/r600_ dri.so file from the stock Alpha-5 libgl1-mesa-dri package (7.6.0~ git20090817. 7c422387- 0ubuntu3) then X will start up correctly with DRI enabled using both the Radeon and Radeon HD drivers.
AIGLX reverts to software rendering as expected.
Acer Aspire 5536 with a Radeon HD 3200 card.