I managed to get Ubuntu installed on a MacBook Pro 16-inch. I compiled kernel 5.5.11 from source with some patches to get it to run. Mostly everything works except the onboard dGPU doesn’t seem to like kernel 5.5. It works just fine with 5.4 and any of the 5.6RC’s (but those versions have problems other parts of the laptop). When using kernel 5.4 or 5.6, the dGPU shows up as Navi 14, since it’s a Radeon Pro 5500M. There seems to be reports out there of linux kernel working with Navi 14 GPU’s, but not for me. I’ve tried using the following bootargs:
amggpu.dpm=0, but nothing seems to work. Only
nomodeset “works”, since it bypassess the GPU entirely (uses llvm, instead).
I would like to try and the get the AMD GPU working with kernel 5.5 since that seems like the path of least resistance.
I know the firmware is available and I’ve updated the initramfs, but still no result. Again, using 5.4 or 5.6 works; just not 5.5.