From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 618273C343C; Mon, 29 Jun 2026 08:22:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782721329; cv=none; b=rW5NPo0pslBXJYc1dDBEfHYtlT4K5IJ5NOUEV3ZUZJQyu4gWD6FE/c/1w1xmOzS4yMQJAy1ttxNv+k9lZL2HwZV+nekessn7IelUb5KjaY3vB9/yofOjI7bbE5ghNOTMir97wYcBKemUFuMJIVzCb0/2iUII1fxHKPa80ZefQfw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782721329; c=relaxed/simple; bh=yKusn79KwbrEg3D9I4t24OWk4gQ1Qu/IOk6Ez3ri9Pg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=oELQUu9b5hj4yuKCvDeO/73oeLELq8x5pMwJe02Kk9NROLYZ+FL6sCMTebk84ZU8iGwAKTLrp52s6LULGhacML+chyl37I2DZxl9H0UoquO3aZFfnmPicfM13UXs/+7lYiCqUEyt5RUglwUlvggkUGa1TxdCIOGchB2J5lrTuLg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=MM/swq+/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="MM/swq+/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DBABE1F00A3F; Mon, 29 Jun 2026 08:22:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782721327; bh=iAxmFHuidiONJITAk4OsD6egnPPOI7pNLRnDMvxzO4w=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=MM/swq+/Q3P9Fov5m3VAhpuj3kXFVIVyWrSteq+Tir1K1zOA/zOWHBEwgHnpStX4E W+kQvbTXjbp/31NabZgkk8HhSpv1ZnlP8aQtaei+/vBpmcwpPwGQ5+HXdjbUS41DvC HqhSmhSnsfsZHcjY32H4oLxt8gIQYr7Bv1B6d4wCi0D6sShp1c1l6GNrbisvk8MkYa DMqfK1l2aqPoTXPtxoOu+sYMgRVGZV+B5iLhwpFJyRJCv1lvgMU4tJcpirrAr8Hs3F g5loHCEMSU6Ut0NgC23qnph9mifKMLmWFdHLXlESnhEE6igi5R+Vfafoq8j8l+MS0s 5FeFNpWysQdAQ== Date: Mon, 29 Jun 2026 09:22:02 +0100 From: Sudeep Holla To: Dmitry Baryshkov Cc: Hans de Goede , Sudeep Holla , "Rafael J . Wysocki" , Bjorn Andersson , Konrad Dybcio , Srinivas Kandagatla , Krzysztof Kozlowski , Dmitry Baryshkov , Bartosz Golaszewski , Abel Vesa , linux-arm-msm@vger.kernel.org, devicetree@vger.kernel.org, linux-acpi@vger.kernel.org Subject: Re: [RFC 00/12] RFC: Devicetree-ACPI hybrid mode Message-ID: <20260629-optimal-vermilion-salamander-0190fc@sudeepholla> References: <20260623145225.143218-1-johannes.goede@oss.qualcomm.com> <20260626-friendly-ammonite-of-holiness-aabefb@sudeepholla> <20260627-miniature-skink-of-superiority-234091@sudeepholla> <2dbfkh3djdrvklsin7zcy53g3wpc76dd4iosxgahbd26zssmx5@zpkplzscllx3> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <2dbfkh3djdrvklsin7zcy53g3wpc76dd4iosxgahbd26zssmx5@zpkplzscllx3> On Sun, Jun 28, 2026 at 10:23:15PM +0300, Dmitry Baryshkov wrote: > On Sat, Jun 27, 2026 at 03:12:31PM +0100, Sudeep Holla wrote: > > On Fri, Jun 26, 2026 at 11:57:47PM +0300, Dmitry Baryshkov wrote: > > > On Fri, Jun 26, 2026 at 04:52:41PM +0100, Sudeep Holla wrote: > > > > On Tue, Jun 23, 2026 at 04:52:13PM +0200, Hans de Goede wrote: > > > > > Hi All, > > > > > > > > > > Currently as soon as the kernel boots with a populated DT provided then > > > > > the arch/arm64 code sets acpi_disabled=1 and the complete ACPI subsystem > > > > > gets disabled. On WoA Snapdragon laptops where the factory Windows OS > > > > > actually boots using these tables this is not necessarily desirable. > > > > > > > > > > > > > I am bit lost reading the very first statement here. > > > > > > > > Who is populating DT and why ? It seems that is the source of the problem. > > > > > > > > If windows can boot with ACPI tables, why is it causing issues for the > > > > Linux kernel, any specifics? > > > > > > Windows uses a separate beast called PEP, which nobody wanted to > > > implement for these platforms up to now. You can find a lot of ACPI > > > dumps for these devices at [1]. > > > > > > > Agreed and I assume that is the reason why we want DT. > > Not completely... Using DT forces us to reimplement bits and pieces for > these laptops. E.g. drivers for EC, battery, etc. > Not entirely clear still. I mean use ACPI for those as well. > > > > > > IOW why is DT populated which creates the problem you are trying to address > > > > here. > > > > > > Most of the laptops resemble other Qualcomm platforms, which use DT for > > > hardware description. In some cases, it is the same platform being used > > > for both mobile, IoT and laptops. It was more or less natural to reuse > > > existing support. > > > > > > > Sure, just use DT then, why are we even talking about mixed/hybrid mode. > > It gives no incentive to OEMs using PEP to get away from it and use > > standard ACPI or improve if anything is missing. > > Well. Here we are talking about the laptops which were being sold since > 2018. I doubt there will be a UEFI update for all these models. > This problem is discussed multiple times and yet OEMs are not interested in fixing it 🙁. > > > > So I don't like this idea of mixing at all. Use ACPI or DT, make up you > > mind. You can't expect to get the best of both worlds if you are not improving > > the missing parts in either of those. This is just a shortcut. > > So, if we need to append the DSDT, what would be the best way to do it? > Something like Surface platform drivers, providing extra device nodes? > CONFIG_ACPI_TABLE_UPGRADE allows to override the ACPI tables via initrd IIRC. -- Regards, Sudeep