From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 04DBED3F095 for ; Wed, 28 Jan 2026 16:11:11 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 273DD10E743; Wed, 28 Jan 2026 16:11:11 +0000 (UTC) X-Greylist: delayed 483 seconds by postgrey-1.36 at gabe; Wed, 28 Jan 2026 16:11:08 UTC Received: from bmailout1.hostsharing.net (bmailout1.hostsharing.net [83.223.95.100]) by gabe.freedesktop.org (Postfix) with ESMTPS id 872B610E73B; Wed, 28 Jan 2026 16:11:08 +0000 (UTC) Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1) server-digest SHA384 client-signature ECDSA (secp384r1) client-digest SHA384) (Client CN "*.hostsharing.net", Issuer "GlobalSign GCC R6 AlphaSSL CA 2025" (verified OK)) by bmailout1.hostsharing.net (Postfix) with ESMTPS id 0299E2C0781D; Wed, 28 Jan 2026 17:03:04 +0100 (CET) Received: by h08.hostsharing.net (Postfix, from userid 100393) id ED2A733097; Wed, 28 Jan 2026 17:03:03 +0100 (CET) Date: Wed, 28 Jan 2026 17:03:03 +0100 From: Lukas Wunner To: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Cc: Jani Nikula , Atharva Tiwari , Ard Biesheuvel , Rodrigo Vivi , Joonas Lahtinen , Tvrtko Ursulin , David Airlie , Simona Vetter , Thomas Zimmermann , Javier Martinez Canillas , "Borislav Petkov (AMD)" , Lenny Szubowicz , Francesco Pompo , linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH v2 2/2] drm/i915/display: Disable display for iMac's Message-ID: References: <20260128145855.1071-1-atharvatiwarilinuxdev@gmail.com> <20260128145855.1071-3-atharvatiwarilinuxdev@gmail.com> <26c4e0b7f9c25f405401288d13fc7e5097e9c7f5@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" 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 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