https://bugs.freedesktop.org/show_bug.cgi?id=26891

--- Comment #51 from Anonymous Helper anonymous@dodgeit.com --- (In reply to comment #50)

You'll need to use vga-switcheroo to select the card you want to use. Then you should be able to start X without any config and it will start on the one selected by vga-switcheroo. Having two device sections as your config does will force X to try and start on both devices.

I tried without the BusID but all I got was a black screen. For some reason when I switch to the intel GPU I get a black screen also, though it did work when I booted from grub-efi earlier with the well documented outb commands to disable AMD (no BIOS from EFI w/o efistub). Not sure if it's an issue with vga-switcheroo, intel driver or something else.

I don't know if it's a problem, but both cards are powered on at boot. I can switch back and forth between the GPUs (though it's tricky doing so blind when on intel graphics).

Any other suggestions? Thanks.