I like to use CodeXL for debugging OpenCL code on an AMD R9 390 GPU.
Therefore I installed Ubuntu 14.04 and the AMD GPU drivers. But after that the internal Intel GPU isn't used anymore, but instead the AMD GPU is used for GUI. Had to connect the display to the AMD GPU. I would prefer to have the GUI using the Intel GPU and the AMD GPU only for OpenCL purposes.
How can I switch that? I tried to chande the xorg.conf but that is overwritten somehow by the AMD drivers which configure it to use the AMD GPU. Any suggestions?