Re: Laptop Working Group Github Issue Request - Multi-GPU Support

Luke Wolf <lukewolf101010@gmail.com> writes:

> The thing is: the AMD version of Optimus works, at least in the 
> AMD +
> AMD configuration. The presence of DRI_PRIME=1 or not will 
> switch which
> GPU is being used on the Framework 16.  I can't comment on the 
> Nvidia
> side because I don't have an example to test on.
>
> I think basically what we need to answer is: "Why is X11's
> autoconfiguration failing in the presence of multi-gpu?".  If 
> that can
> be figured out and fixed then I wouldn't be surprised if that 
> fixes
> Wayland as well and then multi-gpu works as expected. 
> Unfortunately
> that VGA Arbiter log message and it wanting you to manually 
> configure
> the devices is all I have. I can't find where seatd logs (which 
> I
> assume is responsible for this on Wayland's side), and sddm's 
> log
> doesn't seem to provide any clues either.

I know for the Intel+Nvidia Optimus set up, extra information 
about
what the X11 auto configuration should do are installed with the
nvidia-drm-kmod port. Those files tell the auto configuration what 
to
do (at least as I understand it).

Austin Shafer wrote up a good explanation of this in 2023:

https://badland.io/prime-configuration.md

But I don't know how that affects Wayland. The instructions only 
cover
X11.

It seems likely that the auto configuration files for an AMD + AMD 
set
up are missing at least in the X11 case.

Yes, I also find it counter intuitive that automatic configuration
requires files, but I guess it means that X11 can build the 
xorg.conf
itself based on the info from these files (which is a form of
automatic configuration and better than it was in the late 90s 
when I
first encountered X).

Best regards,

-- 
Trenton

[snip]