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=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, T_DKIMWL_WL_HIGH,USER_AGENT_MUTT autolearn=unavailable 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 A7F6DC282DD for ; Mon, 10 Jun 2019 10:32:46 +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 80093206BA for ; Mon, 10 Jun 2019 10:32:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="EBe3ucXm" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 80093206BA 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=I3UXjEn9VoF2oO7gfSw+4Fx+eCH2Ebf0stpGfsBm+YM=; b=EBe3ucXm3/6+EX f7jUtfyw2dRTkvAy9ZvGG0mdubwJBvxt+0WOjvQJa8ie0KcU6EI8eo+VUpeqy/uieX7UYJQ0U7v9Z QHT9D8WOg3oYikyE5nJkuhO19KLRABEyqnKvVSEhbuF6nNj8xE1vl9q0GwmiPz6KSH27Toc1BA6wP hjq0U0ARAhzREIzZX2lYHxdpUWOqN+cUo20Rgn6lNxUedqH4kfOyZibesKUpqrpuJDZbpgffGJl42 5qEMnIKNu+o9gBsQ/NfbsnJfsLeMHwZh+R718Epdf0n+1mKNYJdFs+oZsRdn4y5tQFG62l/k7ngU5 5BNAJmd6VVopsxMkdw+g==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1haHbS-0000CI-UE; Mon, 10 Jun 2019 10:32:38 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1haHbP-0000Be-RC for linux-arm-kernel@lists.infradead.org; Mon, 10 Jun 2019 10:32:37 +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 E092D346; Mon, 10 Jun 2019 03:32:33 -0700 (PDT) Received: from e107155-lin (e107155-lin.cambridge.arm.com [10.1.196.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F383E3F557; Mon, 10 Jun 2019 03:34:12 -0700 (PDT) Date: Mon, 10 Jun 2019 11:32:25 +0100 From: Sudeep Holla To: Bjorn Andersson Subject: Re: [PATCH 00/18] ARM/ARM64: Support hierarchical CPU arrangement for PSCI Message-ID: <20190610103225.GA26602@e107155-lin> References: <20190513192300.653-1-ulf.hansson@linaro.org> <20190607154210.GJ15577@e107155-lin> <20190607193407.GB24059@builder> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190607193407.GB24059@builder> 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-20190610_033235_976996_80BBA22B X-CRM114-Status: GOOD ( 28.77 ) 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 , Ulf Hansson , Geert Uytterhoeven , "Rafael J. Wysocki" , Tony Lindgren , Viresh Kumar , Lina Iyer , Lorenzo Pieralisi , Kevin Hilman , Daniel Lezcano , "Raju P . L . S . S . S . N" , Souvik Chakravarty , Linux PM , linux-arm-msm , Linux ARM , Stephen Boyd , "Rafael J . Wysocki" , Linux Kernel Mailing List , Amit Kucheria , Sudeep Holla , Niklas Cassel 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, Jun 07, 2019 at 12:34:07PM -0700, Bjorn Andersson wrote: > On Fri 07 Jun 08:42 PDT 2019, Sudeep Holla wrote: > > > On Tue, May 14, 2019 at 10:58:04AM +0200, Ulf Hansson wrote: > > > On Tue, 14 May 2019 at 10:08, Rafael J. Wysocki wrote: > > > > > > > > On Mon, May 13, 2019 at 9:23 PM Ulf Hansson wrote: > > > > > > > > > > This series enables support for hierarchical CPU arrangement, managed by PSCI > > > > > for ARM/ARM64. It's based on using the generic PM domain (genpd), which > > > > > recently was extended to manage devices belonging to CPUs. > > > > > > > > ACK for the patches touching cpuidle in this series (from the > > > > framework perspective), but I'm assuming it to be taken care of by > > > > ARM/ARM64 maintainers. > > > > > > Thanks for the ack! Yes, this is for PSCI/ARM maintainers. > > > > > > BTW, apologize for sending this in the merge window, but wanted to > > > take the opportunity for people to have a look before OSPM Pisa next > > > week. > > > > > > > I will start looking at this series. But I would request PSCI/other > > maintainers to wait until we see some comparison data before we merge. > > What comparison are you asking for here? Do you want to see the > improvement this series gives or are you hoping to compare it with some > other mechanism? > OK, I have mentioned this many times already, let me repeat it again. This series adds an alternative to the existing PC mode of CPU idle management. And it's clear that the main reason for the same is the improvement OSI mode offers vs the PC mode. I am asking the comparison for the same. And yes we need to compare apples with apples and not oranges here. > > If they are fine to merge w/o that, I am fine. As of now we have just > > 1-2 platforms to test(that too not so simple to get started) and the > > long term support for them are questionable. > > Why is the support for these platforms questionable? People are actively > working on these platforms and the feature set constantly improving. > Qualcomm will never fix any firmware issues and we need to quirk any bugs found. I would prefer the first platform to minimize those as it would be reference. But I am sure QC won't care about firmware on SDM845 anymore, so not an ideal fit. We need to add support in TF-A to build complete reference story around OSI mode. > > Also with SDM845 supporting PC, we have excellent opportunity to > > compare and conclude the results found. > > That's correct, ATF exists for SDM845. But with the standard choice of > firmware you will get OSI and I don't know of a board out there where > you can switch between them and do a apple to apple comparison. > One that's not PSCI compliant, system must boot in PC. If QC was any serious about this, they would have attempted to fix them in firmware. We have given this comment at-least 4 years back and if that's not still in the current gen products, it says something. Sorry I don't trust the firmware story from QC. > Devices such as RB3 (96boards SDM845), Pixel3 and the Windows laptops > are all OSI only. > Again not fully PSCI compliant. > > So landing this support is not a question of PC or OSI being the better > choice, it's a question of do we want to be able to enter these lower > power states - with the upstream kernel - on any past, present or future > Qualcomm devices. > Nope, I disagree. Better they fix future products. This is a new feature in the kernel with the claim that it's better and since last 2-3 years no efforts are made to prove the claim. So I am not really worried about running low power modes on their past/present devices, but more worried about the precedence this might set with unproven claim and other vendors moving to this without considering all the implications. -- Regards, Sudeep _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel