I just tested graphic drivers 15.11 beta and 15.12.
15.11 beta supports my APU(5750m - 8650G) + linked GPU(m290x)
but 15.12 doesn't support (legacy)8650G BUT i can install it !!
8650G - 15.201.1151.1010
m290x - 15.300.1025.1001.
Two separate drivers working together !!
One is catalyst and second is crimson.
Now my question is... If it was possible before why did you do it impossible with
new drivers ?!