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=-7.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham 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 1C5F2C433DF for ; Thu, 2 Jul 2020 11:41:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EA705207CD for ; Thu, 2 Jul 2020 11:41:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728385AbgGBLlz (ORCPT ); Thu, 2 Jul 2020 07:41:55 -0400 Received: from foss.arm.com ([217.140.110.172]:42548 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727016AbgGBLlz (ORCPT ); Thu, 2 Jul 2020 07:41:55 -0400 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 829D41FB; Thu, 2 Jul 2020 04:41:54 -0700 (PDT) Received: from localhost (unknown [10.1.198.53]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 239563F71E; Thu, 2 Jul 2020 04:41:54 -0700 (PDT) Date: Thu, 2 Jul 2020 12:41:52 +0100 From: Ionela Voinescu To: Viresh Kumar Cc: rjw@rjwysocki.net, catalin.marinas@arm.com, sudeep.holla@arm.com, will@kernel.org, linux@armlinux.org.uk, valentin.schneider@arm.com, mingo@redhat.com, peterz@infradead.org, dietmar.eggemann@arm.com, linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Liviu Dudau Subject: Re: [PATCH 4/8] cpufreq,vexpress-spc: fix Frequency Invariance (FI) for bL switching Message-ID: <20200702114123.GA28120@arm.com> References: <20200701090751.7543-1-ionela.voinescu@arm.com> <20200701090751.7543-5-ionela.voinescu@arm.com> <20200701095414.2wjcnyhndgcedk2q@vireshk-i7> <20200701140735.GB32736@arm.com> <20200702030551.p4cevaahgfvpum4o@vireshk-i7> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200702030551.p4cevaahgfvpum4o@vireshk-i7> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org Hi, On Thursday 02 Jul 2020 at 08:35:51 (+0530), Viresh Kumar wrote: > On 01-07-20, 15:07, Ionela Voinescu wrote: > > On Wednesday 01 Jul 2020 at 16:16:19 (+0530), Viresh Kumar wrote: > > > Is there anyone who cares for this driver and EAS ? I will just skip doing the > > > FIE thing here and mark it skipped. > > > > That is a good question. The vexpress driver is still used for TC2, but > > I don't know of any users of this bL switcher functionality that's part > > of the driver. I think there were a few people wondering recently if > > it's still used [1]. > > Even if it is used by some, there is no need, I believe, to enable > freq-invariance for it, which wasn't enabled until now. > It was enabled until now, but it was partially broken. If you look over the driver you'll see arch_set_freq_scale() being called for both is_bL_switching_enabled() and for when it's not [1]. For !is_bL_switching_enabled() this is fine. But for is_bL_switching_enabled(), it is broken as described in 4/8. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/cpufreq/vexpress-spc-cpufreq.c?h=v5.8-rc3#n203 > And considering that we are going to enable the flag only for the > interested parties now, as from the discussion on 1/8, this shouldn't > be required. > If we just don't want frequency invariance for is_bL_switching_enabled(), I can just guard the setting of the flag suggested by Rafael at 1/8 by !CONFIG_BL_SWITCHER. I'll proceed to do that and remove the fix at 4/8. Many thanks! Ionela. > -- > viresh