Comment 4 for bug 1705609

Hah!

Unfortunately, I cannot reproduce it at the moment. But I did some digging when I *could* reproduce it:

The problem appears when the nvidia driver binds to /dev/fb0 (which I *think* is caused by the firmware selecting it as the boot VGA device?).

When nvidia is driving /dev/fb0, nothing from the is shown on the display (obviously, as the display is hooked up to the Intel), and gpu-detect does *not* detect that it needs offloading.

By switching the fbcon onto /dev/fb1 (via the fbcon=map:1 kernel parameter) I get VT content and can start X on the Intel card by manually modprobing bbswitch, unloading nvidia, “echo OFF | sudo tee /proc/.../bbswitch”, and then starting GDM.

In this situation, by using the xorg.conf I attached, PRIME offload nvidia/intel works fine.

At the moment i915 is binding to /dev/fb0, and gpu-manager/nvidia-settings is working fine switching between Intel and NVIDIA.

What happens to bind to /dev/fb0 seems to be semi-stable - it tends to persist across reboots and power cycling, but it has flipped a couple of times in the past for some reason. The kernel booed does not appear to be the determining factor.

Next time it boots with NVIDIA binding to /dev/fb0 I'll get you the requested log :)