From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sudeep Holla Subject: Re: [PATCH v7 8/8] PCC: Enable PCC only when needed Date: Tue, 21 Jul 2015 10:23:07 +0100 Message-ID: <55AE0F7B.8010804@arm.com> References: <55AD042D.9040204@arm.com> <4609299.WWrJ4WHTsa@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from foss.arm.com ([217.140.101.70]:58758 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752485AbbGUJXL (ORCPT ); Tue, 21 Jul 2015 05:23:11 -0400 In-Reply-To: <4609299.WWrJ4WHTsa@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 23:04, Rafael J. Wysocki wrote: > On Monday, July 20, 2015 03:22:37 PM Sudeep Holla wrote: >> >> On 09/07/15 19:04, Ashwin Chaugule wrote: >>> CPPC is the first client to make use of the PCC Mailbox channel. So >>> enable it only when CPPC is also enabled. >>> >> This sounds like a reverse dependency to me. So if there's some client >> unrelated to CPPC using PCC, CPPC_LIB needs to be selected to enable PCC ? > > No. The other client will need to select PCC too. Yes the PCC users/clients selecting PCC is fine and that's already done(i.e. ACPI_CPPC_LIB selects PCC). I still don't understand the need for this change, also how will other clients possibly select PCC which now depends on CPPC_LIB ? e.g. if we have config ACPI_XYZ_LIB select PCC config ACPI_XYZ select ACPI_XYZ_LIB Won't this shout warning: (ACPI_XYZ_LIB && ACPI_CPPC_LIB) selects PCC which has unmet direct dependencies (MAILBOX && ACPI && ACPI_CPPC_LIB) if ACPI_CPPC_LIB is not selected ? OK, for now we enable ACPI_CPPC_LIB on ARM64 and not on x86. When x86 has a PCC client how will that select PCC without ACPI_CPPC_LIB. Sorry if I am missing to understand something. > > I requested that change, because I'm slightly bothered by the fact that we > build code used by no one by default. > I understand, but will keeping them default off should suffice ? No ? Regards, Sudeep