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Re: [PATCH] PM / OPP: Allow inactive opp_device to be present in dev list

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  Re: [PATCH] PM / OPP: Allow inactive opp_device to be present in dev  list Viresh Kumar <viresh.kumar@linaro.org> - 2016-11-25 08:00 +0100
    Re: [PATCH] PM / OPP: Allow inactive opp_device to be present in dev list "Rafael J. Wysocki" <rafael@kernel.org> - 2016-11-25 17:00 +0100

#1529838 — Re: [PATCH] PM / OPP: Allow inactive opp_device to be present in dev list

On 25-11-16, 12:23, Viresh Kumar wrote:
> Joonyoung Shim reported an interesting problem on his ARM octa-core
> Odoroid-XU3 platform. During system suspend, dev_pm_opp_put_regulator()
> was failing for a struct device for which dev_pm_opp_set_regulator() is
> called earlier.
> 
> This happened because an earlier call to
> dev_pm_opp_of_cpumask_remove_table() function (from cpufreq-dt.c file)
> removed all the entries from opp_table->dev_list apart from the last CPU
> device in the cpumask of CPUs sharing the OPP.
> 
> But both dev_pm_opp_set_regulator() and dev_pm_opp_put_regulator()
> routines get CPU device for the first CPU in the cpumask. And so the OPP
> core failed to find the OPP table for the struct device.
> 
> This patch attempts to fix this problem by adding another field in the
> struct opp_device: inactive.
> 
> Instead of removing the entries from the list during
> dev_pm_opp_of_cpumask_remove_table() function call, we mark them as
> inactive. Such inactive devices will not be used by the core in most of
> the cases, like before, but will be used only at special places which
> need to take inactive devices into account.
> 
> All the devices are removed from the list together now and that happens
> only when the opp_table gets destroyed.
> 
> This patch is tested on Dual A15, Exynos5250 platform by compiling the
> cpufreq-dt driver as a module. The module is inserted/removed multiple
> times with combinations of CPU offline/online steps.
> 
> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>

@Rafael: Can you please add following while applying the patch ?

Cc: <stable@vger.kernel.org> # v4.4+

Somehow git send-email wasn't working properly for me as it was trying
to cc stable@vger.kernel.org#v4.4+ and that was failing. I tried lots
of options including suppress-cc but nothing worked :(

-- 
viresh

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#1530378 — Re: [PATCH] PM / OPP: Allow inactive opp_device to be present in dev list

On Fri, Nov 25, 2016 at 7:55 AM, Viresh Kumar <viresh.kumar@linaro.org> wrote:
> On 25-11-16, 12:23, Viresh Kumar wrote:
>> Joonyoung Shim reported an interesting problem on his ARM octa-core
>> Odoroid-XU3 platform. During system suspend, dev_pm_opp_put_regulator()
>> was failing for a struct device for which dev_pm_opp_set_regulator() is
>> called earlier.
>>
>> This happened because an earlier call to
>> dev_pm_opp_of_cpumask_remove_table() function (from cpufreq-dt.c file)
>> removed all the entries from opp_table->dev_list apart from the last CPU
>> device in the cpumask of CPUs sharing the OPP.
>>
>> But both dev_pm_opp_set_regulator() and dev_pm_opp_put_regulator()
>> routines get CPU device for the first CPU in the cpumask. And so the OPP
>> core failed to find the OPP table for the struct device.
>>
>> This patch attempts to fix this problem by adding another field in the
>> struct opp_device: inactive.
>>
>> Instead of removing the entries from the list during
>> dev_pm_opp_of_cpumask_remove_table() function call, we mark them as
>> inactive. Such inactive devices will not be used by the core in most of
>> the cases, like before, but will be used only at special places which
>> need to take inactive devices into account.
>>
>> All the devices are removed from the list together now and that happens
>> only when the opp_table gets destroyed.
>>
>> This patch is tested on Dual A15, Exynos5250 platform by compiling the
>> cpufreq-dt driver as a module. The module is inserted/removed multiple
>> times with combinations of CPU offline/online steps.
>>
>> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
>
> @Rafael: Can you please add following while applying the patch ?
>
> Cc: <stable@vger.kernel.org> # v4.4+

Yes, I can, but I need an ACK for this from Stephen too.

Thanks,
Rafael

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