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=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 E0882C10F00 for ; Fri, 6 Mar 2020 12:06:55 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id B33AA2072D for ; Fri, 6 Mar 2020 12:06:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="UQlCBKry" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B33AA2072D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=UqM2zCj9sb9dgmde+sLKnz2iiIe8zWSxnZCseRrS8Nw=; b=UQlCBKryBpXz0a FpotSEc4D6ci1QjBvRICv+u0KWLeGy/4N4qUdsW/C0fkCC6kyfkHHpv8DL3O5mqPDYpivfeh8QpPG CR5zzAAZ5wgyAK832lIgAjTVUdBfyfbbSIloijVTBkMUJlHHpD6chNcc3LymlvZnMSbYUZfv6Qdkz F8O6zRTwS0TAaEcuFxxKo1Jp7Z8i5mwawFF6iG5WXHSx8g6zxlTNKVpVdvcX4kDchWCEcooxctUbD WW0xUpkiqXSQQxOxdz7OTtJUDvXrDfeoWfqYanMGdoZsDcCzQ3Pt5vxQhZH9rIL6cWNpu+UfJkt4S 1Dbnq0/ESvsskSPnLteA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jABkj-0007AK-La; Fri, 06 Mar 2020 12:06:53 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jABkg-00079q-SP for linux-arm-kernel@lists.infradead.org; Fri, 06 Mar 2020 12:06:52 +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 DF38D31B; Fri, 6 Mar 2020 04:06:49 -0800 (PST) Received: from bogus (e103737-lin.cambridge.arm.com [10.1.197.49]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5A8CC3F6C4; Fri, 6 Mar 2020 04:06:48 -0800 (PST) Date: Fri, 6 Mar 2020 12:06:46 +0000 From: Sudeep Holla To: Benjamin Gaignard Subject: Re: [PATCH v2 4/4] cpuidle: psci: Allow WFI to be the only state for the hierarchical topology Message-ID: <20200306120646.GB44221@bogus> References: <20200303203559.23995-1-ulf.hansson@linaro.org> <20200303203559.23995-5-ulf.hansson@linaro.org> <20200304122312.GE25004@bogus> <20200305162321.GB53631@bogus> <20200306100431.GA16541@bogus> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200306_040650_963091_29234368 X-CRM114-Status: GOOD ( 19.87 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Ulf Hansson , Lorenzo Pieralisi , Benjamin Gaignard , Linux PM , Stephen Boyd , Daniel Lezcano , "Rafael J . Wysocki" , Lina Iyer , Bjorn Andersson , Sudeep Holla , Linux ARM Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Fri, Mar 06, 2020 at 11:47:40AM +0100, Benjamin Gaignard wrote: > Le ven. 6 mars 2020 =E0 11:04, Sudeep Holla a =E9c= rit : > > > > On Fri, Mar 06, 2020 at 10:28:10AM +0100, Ulf Hansson wrote: > > > On Thu, 5 Mar 2020 at 17:23, Sudeep Holla wrot= e: > > > > > > > > [...] > > > > > > OK. The only state that cluster can enter when CPUs are in WFI are > > > > cluster WFI and most hardware can handle it automatically. I don't = see > > > > the need to do any extra work for that. > > > > > > This isn't about cluster WFI, but about deeper cluster states, such as > > > a cluster-clock-gated-state and a cluster-power-off-state. It's an ST > > > platform, which Benjamin is working on. > > > > > > > Then definitely something is completely wrong. You can't enter deeper > > cluster states(clock-gated and power-off to be specific) with CPU in > > just WFI state. So, if the attempt here is to enter those states, I > > disagree with the change. > > > > Benjamin, please share the complete hierarchical topology for your plat= form. > > The platform is stm32mp157 SoC which embedded two Cortex A7 in one cluste= r. Hang on a minute, is this the same platform where you wanted high resolution timer and were hacking moving dirty tricks around[1]. Now I think you have landed here. > I would like to be able to put the system in a state where clocks of CPUs= and > hardware blocks are gated. In this state local timer are off. Sure, please create a deeper CPU state than WFI and enter so that the CPU state is saved and restored correctly. What is the problem doing that ? > The platform should be allowed to go in this state when the devices > within the power domain are pm_runtime_suspend and the CPUs in WFI. Nope, we don't save and restore state when we enter/exit WFI. And hence we can't allow deeper idle states in the hierarchy. No more discussion on that. > In DT I have one system power domain where the hardware blocks (i2, > uart; spi, etc..) are attached + a power per CPU. You really need a CPU idle state here. -- Regards, Sudeep [1] https://lore.kernel.org/linux-arm-kernel/a42dd20677cddd8d09ea91a369a4e1= 0b@www.loen.fr/ _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel