From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bmailout1.hostsharing.net (bmailout1.hostsharing.net [83.223.95.100]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D7D3326ED40; Wed, 28 Jan 2026 16:03:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=83.223.95.100 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769616193; cv=none; b=f7hVmbg8GC9UR8mSx6fVCjrDnrwXTF6NHlroeZQMiQ1d0G+EO1XNBI7AETDgBCZxgW0RRQZt63ruWSl60Lvq4Fx5NJgBP1VYLfjT8X2h50wREgyLsD7WA6WcU/Aa9dZTszlHQBdOnqjWrVWbfK92k+pyjyTEMlMxQcmCXVWsE3M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769616193; c=relaxed/simple; bh=uMLqevFIr/ee44GujvNqkd8JnuJ2AMLcErLeJSBRGhQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=dHfTKeszyI2c6GGKtHuGAIf4xaB/6VXtd2wkv6oKUKCOFkzBaQ1c6joQMXvmG8lxAeJfKmeeyA7f3XjsJC3KTz9t4gj+uIVI9n8t+qie0beNpzgWAZLeY3uyTnT+mTWp3gb4jc4mNHrt6XAgjdM3Rn/mbg7hpMQZcFrveTXK2Qo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de; spf=none smtp.mailfrom=h08.hostsharing.net; arc=none smtp.client-ip=83.223.95.100 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=h08.hostsharing.net 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> Precedence: bulk X-Mailing-List: linux-efi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: 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