https://bugs.freedesktop.org/show_bug.cgi?id=109345
Michel Dänzer michel@daenzer.net changed:
What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |RESOLVED Resolution|--- |NOTABUG
--- Comment #45 from Michel Dänzer michel@daenzer.net --- Reviewing the information, I'm afraid it's not clear that there's a bug here.
The description says the FirePro is the secondary card in a PCIe 1x slot, whereas the R7 is in the PCIe 16x slot. Thus it seems pretty clear that without explicit configuration, Xorg should be expected to come up on the R7. Arguably it was actually the previous behaviour that was buggy.
Something like this in /etc/X11/xorg.conf should be enough to make Xorg use the FirePro card:
Section "Device" Identifier "whatever" BusID "PCI:5@4096:0:0" EndSection