linux-kernel - Re: [PATCH v2] cpufreq: Don't destroy/realloc policy/sysfs on hotplug/suspend

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Date:	Mon, 14 Jul 2014 12:10:21 -0700
From:	Saravana Kannan <skannan@...eaurora.org>
To:	Viresh Kumar <viresh.kumar@...aro.org>
CC:	"Rafael J . Wysocki" <rjw@...ysocki.net>,
	Todd Poynor <toddpoynor@...gle.com>,
	"linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	"linux-arm-msm@...r.kernel.org" <linux-arm-msm@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	Stephen Boyd <sboyd@...eaurora.org>
Subject: Re: [PATCH v2] cpufreq: Don't destroy/realloc policy/sysfs on hotplug/suspend

On 07/13/2014 11:13 PM, Viresh Kumar wrote:
> On 12 July 2014 08:36, Saravana Kannan <skannan@...eaurora.org> wrote:
>> On 07/10/2014 11:19 PM, Viresh Kumar wrote:
>>
>>>
>>> Please make sure you take care of these issues:
>>> - suspend/resume
>>> - hotplug
>>> - module insert/remove
>>
>> Ok, I was just at the current code. Does cpufreq_unregister_driver() even
>> really work correctly as it stands?
>>
>> It doesn't even seem to stop any of the governors/policies before it just
>> set the cpufreq_driver pointer to NULL.
>>
>> So, technically my v2 patch doesn't even make anything worse when it comes
>> to unregistering the cpufreq driver.
>
> Are you really sure about this? I have tested this *myself* earlier..
>
> subsys_interface_unregister() should take care of stopping/freeing governor
> stuff..
>

I was asking this question based on looking at the code. Didn't actually 
try it -- sent it just before being done for the day. I didn't know 
about the subsys_interface_unregister() coming into play here. I'll take 
a look.

Thanks for the pointer.

-Saravana


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