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 DE577C43603 for ; Fri, 20 Dec 2019 12:01:26 +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 AC89320684 for ; Fri, 20 Dec 2019 12:01:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="ExvCbhYT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AC89320684 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=kat43+mM4iNznAjOLqyPjaVFAgXYrO5BBbIXQdIuwAs=; b=ExvCbhYT+bt5+j 1CsQpPhK2cqE6VupjRDiTWrgBtAEPTDwPUm2/lo2nNg6UzoC9kIP7YbTp3H+d0V+LR+w3gLONk5ov PuN7+gx1dbS+lXKfyNTbRLxqi2mmKV/bJRdlw9HY78N87qVIcXhfVDu9Vb6yPDue+2utz192N72pu KuTC+yxzlDSXkJlSSgY+q5RUjjhQIhHspIRC4SeDgy9ZPpY5ZLPok5lxN0eDlXanTz3N6TiMlr2U1 eUOT882VScX7r53YibtHzR8jDHDBAaFARh/l7NHfF5fr9bB7YNRMYPBofrisrsg2iYaHkd2iBkX8B JA6FFhOgvM8J5tYvbNoA==; 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 1iiGyB-00056B-RS; Fri, 20 Dec 2019 12:01:23 +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 1iiGy8-00055d-3d for linux-arm-kernel@lists.infradead.org; Fri, 20 Dec 2019 12:01:21 +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 6006530E; Fri, 20 Dec 2019 04:01:19 -0800 (PST) Received: from bogus (e107155-lin.cambridge.arm.com [10.1.196.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 613AB3F719; Fri, 20 Dec 2019 04:01:17 -0800 (PST) Date: Fri, 20 Dec 2019 12:01:12 +0000 From: Sudeep Holla To: Ulf Hansson Subject: Re: [PATCH v4 13/14] cpuidle: psci: Add support for PM domains by using genpd Message-ID: <20191220120112.GA26547@bogus> References: <20191211154343.29765-1-ulf.hansson@linaro.org> <20191211154343.29765-14-ulf.hansson@linaro.org> <20191219143427.GF20746@bogus> <20191219180629.GC21846@bogus> <20191220100745.GB6731@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-20191220_040120_238860_0FB0E338 X-CRM114-Status: GOOD ( 23.23 ) 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: Mark Rutland , Lorenzo Pieralisi , Linux PM , Stephen Boyd , linux-arm-msm , Daniel Lezcano , "Rafael J . Wysocki" , Andy Gross , Lina Iyer , Bjorn Andersson , Kevin Hilman , Rob Herring , 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, Dec 20, 2019 at 12:27:39PM +0100, Ulf Hansson wrote: > On Fri, 20 Dec 2019 at 11:07, Sudeep Holla wrote: [...] > > > > Even if you don't create all these genpd domains, it is still degraded > > mode and we are anyway not changing that. Let me know if my understanding > > is wrong here. > > Your understanding is wrong. > > If I remove the genpds because psci_set_osi_mode() fails, then in the > current suggested initialization path, that will lead to that the > entire cpuidle-psci driver will fail to initiate (which is because > psci_dt_attach_cpu() returns an error). In other words, only WFI state > will be used by cpuidle as there will be no cpuidle driver registered > at all. > > That would not be an acceptable behaviour, as it would make the > situation worse than today. > > What we want in this scenario is to keep using all the idle states for > the CPUs, but ignores those for the cluster. That we both agree on, > right? > Yes, I agree and understand that. I was assuming as part of this change you will fixup psci_dt_cpu_init_idle not to return error but just allow CPU level idle. Sorry if that was not clear, I was always assuming that. > > > > I am sure, DTB may get copied to different platform and the firmware may > > not support OSI. I know we have logs, but creating and leaving those > > genpd domains unused will be just confusing. Please change that. > > We are not creating any genpds unless OSI mode is supported. We do not > even try to attach CPUs to the PM domains, unless OSI mode is > supported. So this should already work according to your expectations > and previous requests. > Yes I understand, but checking if "OSI mode is supported" is not same as "setting OSI mode". Until OSI mode is set, it is default/PC mode, so we need to work based on that assumption. > To address your concern about removing genpds when psci_set_osi_mode() > fails, we also need to address the problems we get when calling > psci_dt_attach_cpu(). There are two viable options as I see it. > Shouldn't that fail ? Sorry, I might be missing something. > 1. Prevent calling psci_dt_attach_cpu() altogether when > psci_set_osi_mode() failed. This means another function needs to be > shared from cpuidle-psci-domain.c to let cpuidle-psci.c know about it. > If we don't create any genpd, will psci_dt_attach_cpu fail ? > 2. We can let psci_dt_attach_cpu() return NULL, when > psci_set_osi_mode() failed - as this information is already known by > cpuidle-psci-domain.c. > Yes I was making all the arguments/discussion based on that. Do you see any issues with that ? Any races possible ? > I vote for option 2, but what do you think? > Me too from the time I started the discussion, I assume a lot and don't put this into words in the email. -- Regards, Sudeep _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel