External monitor with iGPU

[vjpr]

I had to disable dGPU because it was crashing on MBP2016.

• Plugging in external monitor while running Ubuntu doesn't detect it.
• Plugging in monitor during boot makes rEFInd boot manager run on it, but then Ubuntu fails tos start...blank screen.

https://gist.github.com/roadrunner2/1289542a748d9a104e7baec6a92f9cd7#using-the-igpu-3-models-only

In order to use an external display (via Thunderbolt/DisplayPort) the dGPU needs to be enabled again (the iGPU is not wired up for that): sudo systemctl disable disable-dgpu

I guess during boot, it is using the dGPU perhaps...

Seems that the thunderbolt ports are wired to the GPU. https://apple.stackexchange.com/questions/263600/does-the-integrated-intel-iris-pro-gpu-support-an-external-display

Tried

sudo modprobe amdgpu enables the gpu. Stops touchpad and keyboard working. External monitor is detected and shows image. But it crashes very soon afterwards.