From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dirk Brandewie Subject: Re: [PATCH 1/2] cpufreq: Add stop callback to cpufreq_driver interface Date: Thu, 20 Mar 2014 08:01:48 -0700 Message-ID: <532B02DC.5000306@gmail.com> References: <1395243954-28262-1-git-send-email-dirk.j.brandewie@intel.com> <1395243954-28262-2-git-send-email-dirk.j.brandewie@intel.com> <3686462.d0rjfgiuqO@vostro.rjw.lan> <2400024.pvKZSBQzVt@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pd0-f181.google.com ([209.85.192.181]:52585 "EHLO mail-pd0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757146AbaCTPBv (ORCPT ); Thu, 20 Mar 2014 11:01:51 -0400 In-Reply-To: <2400024.pvKZSBQzVt@vostro.rjw.lan> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Rafael J. Wysocki" Cc: dirk.brandewie@gmail.com, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, patrick.marlier@gmail.com, viresh.kumar@linaro.org, srivatsa.bhat@linux.vnet.ibm.com, Dirk Brandewie On 03/19/2014 08:28 PM, Rafael J. Wysocki wrote: > On Wednesday, March 19, 2014 11:31:31 PM Rafael J. Wysocki wrote: >> On Wednesday, March 19, 2014 08:45:53 AM dirk.brandewie@gmail.com wrote: >>> From: Dirk Brandewie >>> >>> This callback allows the driver to do clean up before the CPU is >>> completely down and its state cannot be modified. This is used >>> by the intel_pstate driver to reduce the requested P state prior to >>> the core going away. This is required because the requested P state >>> of the offline core is used to select the package P state. This >>> effectively sets the floor package P state to the requested P state on >>> the offline core. >>> >>> Signed-off-by: Dirk Brandewie > > To speed up things a bit I changed the name of the new callback to ->stop_cpu > and made it void. > > I also modified patch [2/2] accordingly and queued the both of them up for 3.15. > > Please check the bleeding-edge branch. > > I wouldn't like to need to do anything like that any more in the future, though. Sorry had appointments yesterday afternoon. bleeding-edge looks good > >>> --- >>> Documentation/cpu-freq/cpu-drivers.txt | 8 +++++++- >>> drivers/cpufreq/cpufreq.c | 3 ++- >>> include/linux/cpufreq.h | 1 + >>> 3 files changed, 10 insertions(+), 2 deletions(-) >>> >>> diff --git a/Documentation/cpu-freq/cpu-drivers.txt b/Documentation/cpu-freq/cpu-drivers.txt >>> index 8b1a445..79def80 100644 >>> --- a/Documentation/cpu-freq/cpu-drivers.txt >>> +++ b/Documentation/cpu-freq/cpu-drivers.txt >>> @@ -61,7 +61,13 @@ target_index - See below on the differences. >>> >>> And optionally >>> >>> -cpufreq_driver.exit - A pointer to a per-CPU cleanup function. >>> +cpufreq_driver.exit - A pointer to a per-CPU cleanup >>> + function called during CPU_POST_DEAD >>> + phase of cpu hotplug process. >>> + >>> +cpufreq_driver.stop - A pointer to a per-CPU stop function >>> + called during CPU_DOWN_PREPARE phase of >>> + cpu hotplug process. >>> >>> cpufreq_driver.resume - A pointer to a per-CPU resume function >>> which is called with interrupts disabled >>> diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c >>> index cf485d9..bb20292 100644 >>> --- a/drivers/cpufreq/cpufreq.c >>> +++ b/drivers/cpufreq/cpufreq.c >>> @@ -1336,7 +1336,8 @@ static int __cpufreq_remove_dev_prepare(struct device *dev, >>> __func__, new_cpu, cpu); >>> } >>> } >>> - } >>> + } else if (cpufreq_driver->stop && cpufreq_driver->setpolicy) >>> + cpufreq_driver->stop(policy); >> >> Nit: Why is it an int function if the only caller doesn't check the >> return value? It should be void. >> >>> >>> return 0; >>> } >>> diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h >>> index 4d89e0e..ff8db19 100644 >>> --- a/include/linux/cpufreq.h >>> +++ b/include/linux/cpufreq.h >>> @@ -224,6 +224,7 @@ struct cpufreq_driver { >>> int (*bios_limit) (int cpu, unsigned int *limit); >>> >>> int (*exit) (struct cpufreq_policy *policy); >>> + int (*stop) (struct cpufreq_policy *policy); >>> int (*suspend) (struct cpufreq_policy *policy); >>> int (*resume) (struct cpufreq_policy *policy); >>> struct freq_attr **attr; >>> >> >> >