linux-kernel - Re: [PATCH v2 1/2] efi/libstub: enable apple-set-os for all apple devices

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Message-ID: <aXs3XOYucVna8eGH@wunner.de>
Date: Thu, 29 Jan 2026 11:33:00 +0100
From: Lukas Wunner <lukas@...ner.de>
To: Atharva Tiwari <atharvatiwarilinuxdev@...il.com>
Cc: airlied@...il.com, ardb@...nel.org, bp@...en8.de,
	dri-devel@...ts.freedesktop.org, francescopompo2@...il.com,
	intel-gfx@...ts.freedesktop.org, intel-xe@...ts.freedesktop.org,
	jani.nikula@...ux.intel.com, javierm@...hat.com,
	joonas.lahtinen@...ux.intel.com, linux-efi@...r.kernel.org,
	linux-kernel@...r.kernel.org, lszubowi@...hat.com,
	rodrigo.vivi@...el.com, simona@...ll.ch, tursulin@...ulin.net,
	tzimmermann@...e.de
Subject: Re: [PATCH v2 1/2] efi/libstub: enable apple-set-os for all apple
 devices

On Thu, Jan 29, 2026 at 04:37:59AM +0000, Atharva Tiwari wrote:
> > As discussed previously, your patch will regress older MacBook Airs
> > which use SPI to access keyboard + trackpad if the set_os protocol
> > is invoked:
> > 
> > https://lore.kernel.org/all/ZoJPgSlZJ3ZlU2zL@wunner.de/
> > 
> > The last time this topic came up, I suggested counting the number of
> > GPUs instead of using the DMI quirk.  I even provided a patch but
> > nobody with an eGPU bothered to test it, so the thread fizzled out:
> > 
> > https://lore.kernel.org/all/Z6paeFrjdv7L3mtv@wunner.de/
> > 
> > Maybe you could give it a spin and verify if it fixes the issue for you?
> 
> I tested your patch, and well it works (you still need the 2nd patch to 
> avoid a blank screen), but i can see how this will fail
> like for example, with the iMacPro (only has dGPU) you would need 2 eGPUs
> to turn on apple-set-os.

I don't quite follow.  The patch counts the number of GPUs and
uses the set_os protocol if there are at least 2 of them.
One dGPU + one eGPU = 2, so the protocol is used.

Am I missing something?

Thanks,

Lukas