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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 E4E62E77188 for ; Fri, 20 Dec 2024 14:10:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=jTxbJCi9/zDDg5XgKoXZDzE87MYo+gwANixgRPH2ZX8=; b=kBAabAhivZRXC55hGd5/QR0Ei8 Y7Ql3KTMYuwMtZZ9SrbSh+yJCbVC5pEF3Y2BCtyVoQjhXxHHKkZbn1qlsjjLxQBnX+qfgURJ3g0Ft pE4wNfQzIMX2ftHZQYsBjlJB4V/2F36V/nkQR62PExpxrPjiPykVMy7tBMdKmCTdd/qeo124b0urn m0IjAdnUIe8xJA15pevp1k4gIwckysX8yZSovP0TwIH0jr1X33Dq4rMkR5AqV7M4KkVqtCYK4wddd eag7+RbCwaw5bN4XA3heXbpe+5kasnNCI4Yu7typZ7HwHgLrCExDDsEVspW38kvSWbkR8Pk1oQTVM ZNgiUwxA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tOdhU-000000056My-0O3I; Fri, 20 Dec 2024 14:09:56 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1tOdTz-000000054Ec-3m2e for linux-arm-kernel@lists.infradead.org; Fri, 20 Dec 2024 13:56:01 +0000 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> 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> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241220_055600_026711_109972C4 X-CRM114-Status: GOOD ( 24.97 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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