From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id A5D101C3F3B; Fri, 20 Dec 2024 13:55:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734702961; cv=none; b=JBo11a8ZEYR5gGfLp0Nbhb1buLJryAuo0tu5UzHOWWKdA8QwrX32JmkaHu6pr8vIPZshEhzgT1cFNTdE8NPuUSZHRgrS/lemGhHXVMjMkZ8Y/SYsZeDyE1GNRx4Sl19YSJR70y5hi3OuGVSq6L3uHox7HNb2lawFBs5N40LhueQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734702961; c=relaxed/simple; bh=qXY5JiIr4Cqs4La6RH/6fpDV63+Jqd7arwepbXYjIfw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=KYCDDDyE2dffLUzrjmwvaJv/1BdtOexQFH6cou+eAWvwWNma+XGaj9ihwY97Dt3WLz4xv0CRLE3uc6hK3ult32zLWi7rqEnMgKq+4FmpowFHFLohnJeqPw0Bi+bYhQJqBqE9WV6tppruckUOZ0913UXD2DeyadmLDRkpUDY3Rg4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id EAA231480; Fri, 20 Dec 2024 05:56:26 -0800 (PST) Received: from bogus (e133711.arm.com [10.1.196.55]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1CC9F3F720; Fri, 20 Dec 2024 05:55:56 -0800 (PST) Date: Fri, 20 Dec 2024 13:55:54 +0000 From: Sudeep Holla To: Konrad Dybcio Cc: Konrad Dybcio , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Lorenzo Pieralisi , Mark Rutland , Marijn Suijten , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Bjorn Andersson Subject: Re: [PATCH 1/3] dt-bindings: arm,psci: Allow S2RAM power_state parameter description Message-ID: References: <20241028-topic-cpu_suspend_s2ram-v1-0-9fdd9a04b75c@oss.qualcomm.com> <20241028-topic-cpu_suspend_s2ram-v1-1-9fdd9a04b75c@oss.qualcomm.com> <54cc4221-ba5f-4741-9033-20874265ca01@oss.qualcomm.com> <349bac70-87e0-4870-a3f0-9f6a3b3e6824@oss.qualcomm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <349bac70-87e0-4870-a3f0-9f6a3b3e6824@oss.qualcomm.com> On Fri, Dec 20, 2024 at 01:54:45PM +0100, Konrad Dybcio wrote: > On 20.12.2024 12:27 PM, Sudeep Holla wrote: > > On Thu, Dec 19, 2024 at 08:43:27PM +0100, Konrad Dybcio wrote: > >> On 6.12.2024 11:21 AM, Sudeep Holla wrote: > >>> On Mon, Oct 28, 2024 at 03:22:57PM +0100, Konrad Dybcio wrote: > >>>> From: Konrad Dybcio > >>>> > >>>> Certain firmware implementations (such as the ones found on Qualcomm > >>>> SoCs between roughly 2015 and 2023) expose an S3-like S2RAM state > >>>> through the CPU_SUSPEND call, as opposed to exposing PSCIv1.0's > >>>> optional PSCI_SYSTEM_SUSPEND. > >>>> > >>> > >>> If so, can you elaborate why s2idle doesn't work as an alternative to what > >>> you are hacking up here. > >> > >> Please see other branches of this thread > >> > >>> > >>>> This really doesn't work well with the model where we associate all > >>>> calls to CPU_SUSPEND with cpuidle. Allow specifying a single special > >>>> CPU_SUSPEND suspend parameter value that is to be treated just like > >>>> SYSTEM_SUSPEND from the OS's point of view. > >>>> > >>>> Signed-off-by: Konrad Dybcio > >>>> --- > >>>> Documentation/devicetree/bindings/arm/psci.yaml | 6 ++++++ > >>>> 1 file changed, 6 insertions(+) > >>>> > >>>> diff --git a/Documentation/devicetree/bindings/arm/psci.yaml b/Documentation/devicetree/bindings/arm/psci.yaml > >>>> index cbb012e217ab80c1ca88e611e7acc06c6d56fad0..a6901878697c8e1ec1cbfed62298ae3bc58f2501 100644 > >>>> --- a/Documentation/devicetree/bindings/arm/psci.yaml > >>>> +++ b/Documentation/devicetree/bindings/arm/psci.yaml > >>>> @@ -98,6 +98,12 @@ properties: > >>>> [1] Kernel documentation - ARM idle states bindings > >>>> Documentation/devicetree/bindings/cpu/idle-states.yaml > >>>> > >>>> + arm,psci-s2ram-param: > >>>> + $ref: /schemas/types.yaml#/definitions/uint32 > >>>> + description: > >>>> + power_state parameter denoting the S2RAM/S3-like system suspend state > >>> > >>> Yet another NACK as this corresponds to PSCI SYSTEM_SUSPEND and as per > >>> specification it takes no such parameter. This is just misleading. > >>> > >> > >> Yeah PSCI_SYSTEM_SUSPEND takes care of this on platforms that expose it. > >> > > > > And those that don't advertise/expose don't get to use, simple. > > The spec says: > > "The call is equivalent to using the CPU_SUSPEND call for the > deepest possible platform powerdown state." > Please take a look at the preconditions for both the calls. They are different. -- Regards, Sudeep