Re: [PATCH] x86/efistub: Add options for forcing Apple set_os protocol

[Lleyton Gray]

I believe this is another issue that requires the same set_os quirk. In 
specific, amdgpu fails to initialize when using an AMD eGPU in a T2 
system, unless the set_os protocol is used. Because it's currently 
quirked for the product names of dual-gpu T2 Macs, if you're on a system 
that doesn't match those names (ex. 2018 Mac Mini), there's no way to 
enable the protocol to get an eGPU working.

On 12/29/24 10:22, Ard Biesheuvel wrote:
> On Sun, 29 Dec 2024 at 11:38, Lukas Wunner <lukas@xxxxxxxxx> wrote:
> > On Sun, Dec 29, 2024 at 11:08:55AM +0100, Ard Biesheuvel wrote:
> > > IIRC, the original issue is about not being able to use the discrete
> > > GPU with the built-in panel, and the issue about an external GPU did
> > > come up in the discussion - however, this does not affect the built-in
> > > panel at all.
> > The original issue was that the integrated GPU is hidden (powered off)
> > unless the set_os protocol is used.  So only the discrete GPU is
> > available, which results in terrible battery life.  Using set_os
> > keeps the iGPU exposed so the OS can switch to it and power off
> > the dGPU.
> OK, thanks for clearing that up.
>
> But this is distinctly different from the eGPU case we are dealing with here.
>
> > We could have solved this by checking whether there are two PCI devices
> > with VGA class in the system.  But that would have triggered in the
> > iGPU + eGPU case.  We wanted to avoid that and thus quirked for the
> > DMI product names instead.
> Yeah, so it would be good to know what issue are trying to fix with this patch.