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 697A7C10DCE for ; Fri, 6 Mar 2020 10:04:48 +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 36CCE2072D for ; Fri, 6 Mar 2020 10:04:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="E9vMte75" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 36CCE2072D 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=VQhJZlVwtO4QqHixsi9NKyR9xpjYuQDhxYG58+m6iDc=; b=E9vMte75heNVcI +MIIfghRzufdC/XV4Legmy/H5S34hqQL5MSYHx9ZGf/ywfogB998FS+hDIEENFRcxqpIthBCvLsTJ 9Fr2LAvmDZ5Qowa0Gb9xSiq0wXTmIk9ecSJJUYi4Bv6ATHDjUejIp1ToCvQV52gsPXPXowbpArnEa zWdRZihscKey672eRmVld7PWn75eYD3m8PMaU/nIBZ3bS+dsCSlEJQk6T3T0JYbqUGr4flrr5EdLB e18LkoNeB+hgo3HIdBWd0NiK/7GyzP24H+5hf4LTzmDsEa3P9QrIJabe/XKRIFsrk9YwfICsAl5bs 87ubBEIfWy/JUcaOov0g==; 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 1jA9qZ-00027G-Ic; Fri, 06 Mar 2020 10:04:47 +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 1jA9qW-00026b-63 for linux-arm-kernel@lists.infradead.org; Fri, 06 Mar 2020 10:04:45 +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 5298C31B; Fri, 6 Mar 2020 02:04:40 -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 C16CB3F6C4; Fri, 6 Mar 2020 02:04:38 -0800 (PST) Date: Fri, 6 Mar 2020 10:04:31 +0000 From: Sudeep Holla To: Ulf Hansson Subject: Re: [PATCH v2 4/4] cpuidle: psci: Allow WFI to be the only state for the hierarchical topology Message-ID: <20200306100431.GA16541@bogus> References: <20200303203559.23995-1-ulf.hansson@linaro.org> <20200303203559.23995-5-ulf.hansson@linaro.org> <20200304122312.GE25004@bogus> <20200305162321.GB53631@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_020444_272948_D43F9567 X-CRM114-Status: GOOD ( 19.13 ) 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: 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="us-ascii" Content-Transfer-Encoding: 7bit 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 10:28:10AM +0100, Ulf Hansson wrote: > On Thu, 5 Mar 2020 at 17:23, Sudeep Holla wrote: > > [...] > > 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 platform. > > > > > Then, after we have called pm_runtime_put_sync_suspend() a few lines > > > above, we may potentially have a "domain state" to use, instead of the > > > WFI state. > > > > > > > Are they any platforms with this potential "domain state" to use with > > CPU WFI. I want to understand this better. > > > > > In this case, if we would have called psci_enter_state(), that would > > > lead us to calling cpu_do_idle() from the __CPU_PM_CPU_IDLE_ENTER() > > > macro, becuase idx is zero. In other words, the domain state would > > > become unused. > > > > > > > For a domain state to become unused with WFI, it needs to be available > > and I am not 100% sure of that. > > With these changes from the series, we can fully conform to the > hierarchical DT bindings for PSCI. > Theoretically may be, but may not confirm to the hardware states. > I am not sure I understand your concern, is there a cost involved by > applying this? > Yes as mentioned above. -- Regards, Sudeep _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel