site  contact  subhomenews

Proposal to support modern AMD GPUs

December 31, 2020 — BarryK

I recently posted about compiling the 5.10.3 kernel, and asked about configuration options to support AMD GPUs. I received an email today from someone identifying themselves as "Anonymous", with link to an ArchWiki site:

The Gentoo people also have a wiki page on the AMD GPU:

As I understand it, the kernel 'radeon.ko' module is for older AMD GPUs, the 'amdgpu.ko' module is for newer GPUs.

All right, so if I enable CONFIG_DRM_AMDGPU_SI (Southern Islands GPU) and CONFIG_DRM_AMDGPU_CIK (Sea Islands GPU) next time that I compile the 5.10.x kernel, what other changes will be required so that AMD GPU support will work seamlessly?

I want everything to be automatic. Interesting, the Arch wiki advises to make sure that 'amdgpu.ko' loads before 'radeon.ko', whereas the Gentoo wiki advises to blacklist 'radeon.ko' for modern GPUs. I really do not want to blacklist the radeon module if it is required for older GPUs.

Trying to interpret these wikis, they seem to imply, but don't really say, that 'radeon.ko' will work with the modern SI and CIK GPUs.

Anyway, my proposal is to enable those two config options, and create this file, /etc/modprobe.d/amd.conf:

options amdgpu si_support=1
options amdpgu cik_support=1
options radeon si_support=0
options radeon cik_support=0
softdep radeon pre: amdgpu

...don't know about that "softdep" entry though! Just thinking about module loading order. Or, could do it this way:

softdep amdgpu post: radeon

...or maybe the kernel will load them in correct order anyway, without this.

I don't have any AMD-based computers, they are all Intel chipsets. Maybe I should buy a cheap computer with modern AMD chipset?   

Tags: easy