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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CD465C352A1 for ; Wed, 5 Feb 2020 15:55:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A4ABA217BA for ; Wed, 5 Feb 2020 15:55:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="Nbq5QFkL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727716AbgBEPzz (ORCPT ); Wed, 5 Feb 2020 10:55:55 -0500 Received: from mail-vs1-f65.google.com ([209.85.217.65]:42972 "EHLO mail-vs1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727524AbgBEPzy (ORCPT ); Wed, 5 Feb 2020 10:55:54 -0500 Received: by mail-vs1-f65.google.com with SMTP id b79so1626053vsd.9 for ; Wed, 05 Feb 2020 07:55:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ei9H45SV2oMs69C7hL0SyaAz256oxS6zCX5MjvjcWsU=; b=Nbq5QFkLGVrepL0kiN0uMOeJSiQzYs0SIsaGXzuFw02d55rgJXVER2UguTreuVRGJO Od4xBaxLrJDFSjE6bsj/+aUv9g+rYikRSWZyUQledbdk/qhAy29jK+vcs1DSM5HzxPuO c5BOqGKN/1CIxVjv2yrQJRe4hCvPMRT57oeV36R1VPLE01xb9GAo9MxqQEOTMXvDJNZk zkaFAQgOgMOYJxNPMgclviF2hmrn2Yfp6AO3+sQxJIajd3Ok/x+B0cgXXgWrzRXYHfKd fpR95zPsC6lrCVdelVsr4LatgdvMAc1Y+1iJx5DWEh/KAgqOL/zuXYPqb5PRsywUb1/s Ze9Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ei9H45SV2oMs69C7hL0SyaAz256oxS6zCX5MjvjcWsU=; b=StdgteiPVuXgGXXSRZR4YJibF+G/3Rd1E3otuFkcyqDA4MBe4JFewCEYfVEyekbmiq 5GJzP1bJRXtl0y68+Oe1/wy5CYi7fbWJ7m0Plr2vsGy+AR6P8IsS4SSTJ2VF8440fK8w cwZ1QE6FJg97a9tWQezqzL5iYmw7XWbVFZN1nEIvr78gSzgW9B+QeGkfkW1RSyTbH1OF VRe4YBij7QZVwenieDjSEj/Di2/URdbGxAIFQ4fIQudeyq1SYw73ytYg65AIKea1eMDl Sxc/vrVpCE0gAXPB5OEJyURsHLYPccvqvJCDMJR12MAU5q+x/lvkv12zeksA0U1PkJUN n3qg== X-Gm-Message-State: APjAAAUTHnykDcnX/FFqdkqkJXhOMCH0TkGh4pn7qvWITFyCuFZOubqI seKbb6bwpbqtzEQYi1lD3L2Pd+rQ4prxYf5t9Lc6Xw== X-Google-Smtp-Source: APXvYqwSSPQAZY6rLGXHvigKNLyKPELRR7aaS7nR0axlfGQtU2mVxCkKTFTO+6ddkXy//tB9BMu4/9jHYzXyjFWuYuM= X-Received: by 2002:a05:6102:757:: with SMTP id v23mr22937800vsg.35.1580918153583; Wed, 05 Feb 2020 07:55:53 -0800 (PST) MIME-Version: 1.0 References: <1580736940-6985-1-git-send-email-mkshah@codeaurora.org> <1580736940-6985-6-git-send-email-mkshah@codeaurora.org> <20200203170832.GA38466@bogus> <0d7f7ade-3a1e-5428-d851-f1a886f58712@codeaurora.org> <20200204152132.GA44858@bogus> <6ff7c82d-4204-a339-4070-0154ab4515f1@codeaurora.org> <20200205140603.GB38466@bogus> In-Reply-To: <20200205140603.GB38466@bogus> From: Ulf Hansson Date: Wed, 5 Feb 2020 16:55:17 +0100 Message-ID: Subject: Re: [PATCH v3 5/7] drivers: firmware: psci: Add hierarchical domain idle states converter To: Sudeep Holla Cc: Maulik Shah , Stephen Boyd , Andy Gross , David Brown , Lorenzo Pieralisi , linux-arm-msm , Linux Kernel Mailing List , Linux PM , Linux ARM , Bjorn Andersson , Evan Green , Doug Anderson , Rajendra Nayak , Lina Iyer , lsrao@codeaurora.org, "Rafael J. Wysocki" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 5 Feb 2020 at 15:06, Sudeep Holla wrote: > > On Wed, Feb 05, 2020 at 05:53:00PM +0530, Maulik Shah wrote: > > > > On 2/4/2020 8:51 PM, Sudeep Holla wrote: > > > On Tue, Feb 04, 2020 at 10:22:42AM +0530, Maulik Shah wrote: > > > > On 2/3/2020 10:38 PM, Sudeep Holla wrote: > > > > > On Mon, Feb 03, 2020 at 07:05:38PM +0530, Maulik Shah wrote: > > > > > > From: Ulf Hansson > > > > > > > > > > > > If the hierarchical CPU topology is used, but the OS initiated mode isn't > > > > > > supported, we need to rely solely on the regular cpuidle framework to > > > > > > manage the idle state selection, rather than using genpd and its > > > > > > governor. > > > > > > > > > > > > For this reason, introduce a new PSCI DT helper function, > > > > > > psci_dt_pm_domains_parse_states(), which parses and converts the > > > > > > hierarchically described domain idle states from DT, into regular flattened > > > > > > cpuidle states. The converted states are added to the existing cpuidle > > > > > > driver's array of idle states, which make them available for cpuidle. > > > > > > > > > > > And what's the main motivation for this if OSI is not supported in the > > > > > firmware ? > > > > Hi Sudeep, > > > > > > > > Main motivation is to do last-man activities before the CPU cluster can > > > > enter a deep idle state. > > > > > > > Details on those last-man activities will help the discussion. Basically > > > I am wondering what they are and why they need to done in OSPM ? > > > > Hi Sudeep, > > > > there are cases like, > > > > Last cpu going to deepest idle mode need to lower various resoruce > > requirements (for eg DDR freq). > > > > In PC mode, only PSCI implementation knows the last man and there shouldn't > be any notion of it in OS. If you need it, you may need OSI. You are still > mixing up the things. NACK for any such approach, sorry. Sudeep, I don't quite agree with your NACK to this. At least not yet. :-) I do agree that the best suited solution seems to be OSI, as to support this kind of SoC requirements. However, if for some reason the PC mode is being used, we could still allow Linux to control "last-man activities" as it knows what each CPU has voted for when going idle. Yes, the PSCI FW decides in the end, but that doesn't really matter. Or is there another technical reason to why you object? As a matter of fact, if we allow support for PC mode with "last-man-activities", it would allow us to make a fair performance/energy comparison between the two PSCI CPU suspend modes, for the same SoC. I would be thrilled about looking into doing such tests, I bet you are as well!? Kind regards Uffe