/etc/bumblebee/xorg.conf.radeon

Section "ServerLayout"
    Identifier     "Layout0"
    Screen         "Screen0"
    Option         "AutoAddDevices" "false"
EndSection

Section "Device"
    Identifier     "Device0"
    Driver         "radeon"
    BusID  "PCI:1:0:0"
EndSection

Section "Screen"
    Identifier     "Screen0"
    Device         "Device0"
EndSection