Re: [PATCH v2 2/2] drm/i915/display: Disable display for iMac's

Lukas Wunner
2026-01-28T16:03:11Z

On Wed, Jan 28, 2026 at 05:37:18PM +0200, Ville Syrjälä wrote:
> On Wed, Jan 28, 2026 at 05:23:51PM +0200, Jani Nikula wrote:
> > On Wed, 28 Jan 2026, Atharva Tiwari <atharvatiwarilinuxdev@gmail.com> wrote:
> > > Disable display on iMacs, as they can't do link training
> > > on the internal display.
> > >
> > > (tested on iMac20,1)
>
> I guess the main problem with a hack like this is that you won't
> be able to get deep pkgC states due to the display hardware not
> going into DC5/6.

If patch [1/2] in this series results in a power regression,
I'd say it needs to be reworked. Either exclude iMacs from
the set_os protocol or find a way to power down the iGPU again
once the kernel has assumed control.

I wonder what macOS does. If the iGPU is exposed by set_os,
surely macOS must be able to power down the iGPU again,
so we should be doing the same.

Thanks,

Lukas