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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A9EDDC433FE for ; Wed, 11 May 2022 14:22:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243487AbiEKOW1 (ORCPT ); Wed, 11 May 2022 10:22:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232954AbiEKOW0 (ORCPT ); Wed, 11 May 2022 10:22:26 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 0255E62CFF; Wed, 11 May 2022 07:22:25 -0700 (PDT) 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 CD59EED1; Wed, 11 May 2022 07:22:24 -0700 (PDT) Received: from bogus (e103737-lin.cambridge.arm.com [10.1.197.49]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 24B343F66F; Wed, 11 May 2022 07:22:23 -0700 (PDT) Date: Wed, 11 May 2022 15:22:20 +0100 From: Sudeep Holla To: Pierre Gondois Cc: linux-kernel@vger.kernel.org, Ionela.Voinescu@arm.com, Sudeep Holla , Dietmar.Eggemann@arm.com, "Rafael J. Wysocki" , Len Brown , Viresh Kumar , Robert Moore , linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org, devel@acpica.org Subject: Re: [PATCH v1 2/5] ACPI: bus: Set CPPC _OSC bits for all and when CPPC_LIB is supported Message-ID: <20220511142220.sjfhikuf6fydnrkb@bogus> References: <20220511134559.1466925-1-pierre.gondois@arm.com> <20220511134559.1466925-2-pierre.gondois@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220511134559.1466925-2-pierre.gondois@arm.com> Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Wed, May 11, 2022 at 03:45:56PM +0200, Pierre Gondois wrote: > The _OSC method allows the OS and firmware to communicate about > supported features/capabitlities. It also allows the OS to take > control of some features. > > In ACPI 6.4, s6.2.11.2 Platform-Wide OSPM Capabilities, the CPPC > (resp. v2) bit should be set by the OS if it 'supports controlling > processor performance via the interfaces described in the _CPC > object'. > > The OS supports CPPC and parses the _CPC object only if > CONFIG_ACPI_CPPC_LIB is set. Replace the x86 specific > boot_cpu_has(X86_FEATURE_HWP) dynamic check with an arch > generic CONFIG_ACPI_CPPC_LIB build-time check. > > Note: > CONFIG_X86_INTEL_PSTATE selects CONFIG_ACPI_CPPC_LIB. While this is work as per the spec, by not sure what kind of ACPI firmware are in the wild. So be prepared to relax/constrain to original feature check for x86, unfortunate but may be needed. Anyways, Reviewed-by: Sudeep Holla -- Regards, Sudeep