linux-kernel - Re: [PATCH v3 0/2] efi/x86: Call set

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Message-ID: <ZpgUVjjj3naBGtfO@wunner.de>
Date: Wed, 17 Jul 2024 20:58:30 +0200
From: Lukas Wunner <lukas@...ner.de>
To: Aditya Garg <gargaditya08@...e.com>
Cc: Ard Biesheuvel <ardb+git@...gle.com>,
	"linux-efi@...r.kernel.org" <linux-efi@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Ard Biesheuvel <ardb@...nel.org>,
	Hans de Goede <hdegoede@...hat.com>,
	Kerem Karabay <kekrby@...il.com>,
	Orlando Chamberlain <orlandoch.dev@...il.com>,
	"sharpenedblade@...ton.me" <sharpenedblade@...ton.me>
Subject: Re: [PATCH v3 0/2] efi/x86: Call set_os() protocol on dual GPU Macs

On Wed, Jul 17, 2024 at 04:35:15PM +0000, Aditya Garg wrote:
> For the Macs having a single GPU, in case a person uses an eGPU,
> they still need this apple-set-os quirk for hybrid graphics.

I don't quite follow.  You mean the integrated graphics are
disabled by EFI firmware if an eGPU is attached?

This sounds like a bug on Apple's part:  The panel can be switched
between integrated graphics and discrete graphics, but an external
display can't be switched between eGPU and iGPU.  Is the person
affected using the latest EFI firmware update from Apple?

We need more information before we can devise a way to solve the
issue:

- Exact model name
  (I'd be surprised if this affected pre-Haswell models)
- Full dmesg output with command line option "dump_apple_properties"
  (EFI drivers provide various properties for Thunderbolt-attached
  devices and graphics cards, those could be queried to recognize
  the situation causing the issue)
- Full lspci output with and without eGPU attached

Perhaps you can open a bug at bugzilla.kernel.org and attach the
files there.

Thanks,

Lukas