Re: [PATCH v2 0/2] Add support for eGPUs on Apple Products

[Lukas Wunner]

On Wed, Jan 28, 2026 at 02:58:36PM +0000, Atharva Tiwari wrote:
> This series adds support for eGPUs on Apple products, by
> enabling apple-set-os on all apple devices.
> 
> A side effect of this patch is that the iGPU becomes enabled on iMacs.
> However, iMacs can’t use the iGPU to drive the display
> (They can't link-train the internal display),
> so displays must be disabled on iMacs.

Oh there's the explanation that should have been in the commit message
of patch [2/2].

It's possible that the iMac has a multiplexer built-in which can
switch between the iGPU and dGPU at runtime.  Please ensure that
you have set CONFIG_APPLE_GMUX=y in your .config, the gmux driver
should bind to the multiplexer if there is one.

If there is a multiplexer built-in, then disabling the iGPU is the
wrong approach.

Thanks,

Lukas