From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sudeep Holla Subject: Re: [PATCH v7 5/8] CPPC: Add a CPUFreq driver for use with CPPC Date: Tue, 21 Jul 2015 09:52:14 +0100 Message-ID: <55AE083E.80303@arm.com> References: <55AD0411.4000603@arm.com> <3774934.MfIr66XDWO@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from foss.arm.com ([217.140.101.70]:58674 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752485AbbGUIwS (ORCPT ); Tue, 21 Jul 2015 04:52:18 -0400 In-Reply-To: <3774934.MfIr66XDWO@vostro.rjw.lan> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: "Rafael J. Wysocki" Cc: Sudeep Holla , Ashwin Chaugule , "jaswinder.singh@linaro.org" , "linux-pm@vger.kernel.org" , "linux-acpi@vger.kernel.org" , "linaro-acpi@lists.linaro.org" , "patches@linaro.org" , "viresh.kumar@linaro.org" On 20/07/15 23:07, Rafael J. Wysocki wrote: > On Monday, July 20, 2015 03:22:09 PM Sudeep Holla wrote: >> >> On 09/07/15 19:04, Ashwin Chaugule wrote: >>> This driver utilizes the methods introduced in the previous >>> patch - "ACPI: Introduce CPU performance controls using CPPC" >>> and enables usage with existing CPUFreq governors. >>> >>> Signed-off-by: Ashwin Chaugule >>> Reviewed-by: Al Stone >>> --- >>> drivers/cpufreq/Kconfig.arm | 16 ++++ >>> drivers/cpufreq/Makefile | 2 + >>> drivers/cpufreq/cppc_cpufreq.c | 197 +++++++++++++++++++++++++++++++++++++++++ >>> 3 files changed, 215 insertions(+) >>> create mode 100644 drivers/cpufreq/cppc_cpufreq.c >>> >>> diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm >>> index 4f3dbc8..578384d 100644 >>> --- a/drivers/cpufreq/Kconfig.arm >>> +++ b/drivers/cpufreq/Kconfig.arm >>> @@ -272,3 +272,19 @@ config ARM_PXA2xx_CPUFREQ >>> This add the CPUFreq driver support for Intel PXA2xx SOCs. >>> >>> If in doubt, say N. >>> + >>> +config ACPI_CPPC_CPUFREQ >>> + tristate "CPUFreq driver based on the ACPI CPPC spec" >>> + depends on ACPI_CPPC_LIB >>> + default n >>> + help >>> + This adds a CPUFreq driver which uses CPPC methods >>> + as described in the ACPIv5.1 spec. CPPC stands for >>> + Collaborative Processor Performance Controls. It >>> + is based on an abstract continuous scale of CPU >>> + performance values which allows the remote power >>> + processor to flexibly optimize for power and >>> + performance. CPPC relies on power management firmware >>> + for its operation. >> >> Why is this ARM specific ? It might be used only on ARM but doesn't mean >> it should be visible only on ARM ACPI systems. > > Why bother people with considering Kconfig options that are useless to them? > I agree to some extent, but main worry is that we are then making these features architecture specific while ACPI is supposed to be architecture agnostic. I was just trying to avoid doing so. Regards, Sudeep