Sometimes I have to use a cheapo laptop I bought back in summer but it was still cool, because I could combine both the APU and discrete AMD graphics to render 2-3 times faster than the quadcore CPU would, until recently.
On version 2.77-2.78, the tiles corresponding to the faster GPU appear grayish, with just a silhouette of the render while on the latest 2.78a release the two GPUs can't seem to render together at all. If I go back to 2.76a however, all renders fine like it used to.
I've changed settings, uninstalled and installed video drivers and Blender, tried everything but still same results. What is going on?!!!