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 2024F1FC0E1; Fri, 6 Dec 2024 10:24:30 +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=1733480673; cv=none; b=e/RMwDTQ44+IDwJxGIXzRCdTFUuyYcI7QmiAc3HD+PL3OaQbkbDCL5RFFy4U4kc0nSBDOTc9ty0LpHR6eKqAbkoUj12W+C/59Kvm/t1q4j54m+hheSJuQAy3sfYUdFdpkjz6Cb89h6Pcr9OvYtlcc0S0yoZS8R5lzMTCI35RIHc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733480673; c=relaxed/simple; bh=kcUa+zTRzcdPhK9IlN/bpQh3o7vKfSJFKnw4RPuVXwQ=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=MOkgCG+1iiQrAHFYfsHPZSXq0m+aTYjI6xVNPAC+ys5JzmsuRD7sHfYAPH+fRdIfE8sqAGMb8HhGCZpfvDwht6ZqN9/IURi+3l+P2uBAUhCwDFBoBO+GxLL3CrNXiaRseJcDRIcZZqW4q9636lVweRbqaCo7mUCDoiCjZ/68hB0= 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 4F10D12FC; Fri, 6 Dec 2024 02:24:52 -0800 (PST) Received: from bogus (e133711.arm.com [10.1.196.55]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 6B87B3F71E; Fri, 6 Dec 2024 02:24:22 -0800 (PST) Date: Fri, 6 Dec 2024 10:24:19 +0000 From: Sudeep Holla To: Lorenzo Pieralisi Cc: Konrad Dybcio , Rob Herring , Sudeep Holla , Krzysztof Kozlowski , Conor Dooley , Mark Rutland , Marijn Suijten , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Bjorn Andersson , Konrad Dybcio Subject: Re: [PATCH 3/3] firmware/psci: Allow specifying an S2RAM state through CPU_SUSPEND Message-ID: References: <20241028-topic-cpu_suspend_s2ram-v1-0-9fdd9a04b75c@oss.qualcomm.com> <20241028-topic-cpu_suspend_s2ram-v1-3-9fdd9a04b75c@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: On Wed, Nov 13, 2024 at 01:57:23PM +0100, Lorenzo Pieralisi wrote: > On Mon, Oct 28, 2024 at 03:22:59PM +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. > > > > This works exactly like SYSTEM_SUSPEND. The PSCI spec describes that > > call as optional (and only introduced in PSCIv1.0), so not all > > platforms expose it. > > > > Marking a DT-described "domain-idle-state" as such isn't currently > > well accounted for in the PSCI idle topology infrastructure: the > > cpuidle and genpd framework are deeply intertwined, and trying to > > separate them would cause more havoc than good. > > I don't understand what you mean here please elaborate. > > The part of the story I understand is that you have a system (well, > firmware for an extended set of systems) that does not implement > SYSTEM_SUSPEND but can reach a S2R like system state through the > CPU_SUSPEND call. Firmware works in OS-initiated mode, idle-states > should allow you to define idle states that allow the system to > enter the S2R state through CPUidle. > > Please explain to me what's missing. > > > Instead, allow the specifying of a single CPU_SUSPEND sleep param > > under the /psci node that shall be treated exactly like SYSTEM_SUSPEND > > from Linux's POV. As a bonus, this way we also don't have to fight > > with the genpd idle governor to avoid taking the S3-like state into > > consideration. > > That's not acceptable. I want to understand what's preventing this > system to enter that state through suspend2idle and the mainline code. > > > Signed-off-by: Konrad Dybcio > > --- > > drivers/firmware/psci/psci.c | 36 +++++++++++++++++++++++++++++++----- > > 1 file changed, 31 insertions(+), 5 deletions(-) > > NACK > +1, will wait for the response here before adding any more questions that may lead to more confusion or discussion churn. -- Regards, Sudeep