Comment 2 for bug 1230008

I guess it is a conflict with PRIME functionality, this is from the Xorg.0.log:

[ 18.478] (--) PCI: (0:1:0:0) 10de:1292:1043:122d rev 161, Mem @ 0xf6000000/16777216, 0xe0000000/268435456, 0xf0000000/33554432, I/O @ 0x0000e000/128, BIOS @ 0x????????/524288

You can try creating /etc/X11/xorg.conf.d/prevent-auto-gpu.conf, and then reboot/re-login. Check your Xorg.0.log and that line should be gone.

Section "ServerLayout"
    Identifier "DefaultLayout"
    Option "AutoAddGPU" "false"