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=-2.2 required=3.0 tests=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 E5AC3C433E1 for ; Wed, 17 Jun 2020 12:48:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CBAE220DD4 for ; Wed, 17 Jun 2020 12:48:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726634AbgFQMsC (ORCPT ); Wed, 17 Jun 2020 08:48:02 -0400 Received: from foss.arm.com ([217.140.110.172]:57334 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725860AbgFQMsB (ORCPT ); Wed, 17 Jun 2020 08:48:01 -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 6E62E1042; Wed, 17 Jun 2020 05:48:01 -0700 (PDT) Received: from bogus (unknown [10.37.12.89]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C35E93F6CF; Wed, 17 Jun 2020 05:47:59 -0700 (PDT) Date: Wed, 17 Jun 2020 13:47:53 +0100 From: Sudeep Holla To: Nicola Mazzucato , viresh.kumar@linaro.org Cc: linux-kernel@vger.kernel.org, rjw@rjwysocki.net, linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org, lukasz.luba@arm.com, Sudeep Holla Subject: Re: [PATCH 2/2] cpufreq: arm_scmi: Set fast_switch_possible conditionally Message-ID: <20200617124753.GA15211@bogus> References: <20200617094332.8391-1-nicola.mazzucato@arm.com> <20200617094332.8391-2-nicola.mazzucato@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200617094332.8391-2-nicola.mazzucato@arm.com> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 17, 2020 at 10:43:32AM +0100, Nicola Mazzucato wrote: > Currently the fast_switch_possible flag is set unconditionally > to true. Based on this, schedutil does not create a > thread for frequency switching and would always use the > fast switch path. > However, if the platform does not support frequency > fast switch, this may cause the governor to attempt an > operation that is not supported by the platform. > > Fix this by correctly retrieve the fast_switch capability > from the driver which knows if the platform can support > this feature. > Hi Viresh, This is first step towards avoiding polling based cpufreq set if firmware has fast access registers that bypass normal mailbox based messaging. If you happy with this and provide ack, I will take this along with scmi changes via ARM SoC. Hope that is fine by you. -- Regards, Sudeep