From: Viresh Kumar <viresh.kumar@linaro.org>
To: Radivoje Jovanovic <radivoje.jovanovic@linux.intel.com>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Punit Agrawal <punit.agrawal@arm.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux PM <linux-pm@vger.kernel.org>,
Zhang Rui <rui.zhang@intel.com>,
Eduardo Valentin <edubezval@gmail.com>,
Radivoje Jovanovic <radivoje.jovanovic@intel.com>
Subject: Re: [PATCH] thermal/cpu_cooling: remove local cooling state variable
Date: Mon, 3 Aug 2015 08:43:25 +0530 [thread overview]
Message-ID: <20150803031325.GU899@linux> (raw)
In-Reply-To: <20150801113405.GL899@linux>
On 01-08-15, 17:04, Viresh Kumar wrote:
> On 31-07-15, 08:30, Radivoje Jovanovic wrote:
> > I agree with you that this patch is trivial for the current
> > implementation since the notifier, as it is currently, will enforce
> > cpu_cooling policy change at every CPUFREQ_ADJUST which would cause
> > problems in our current implementation. In our implementation there is
> > a cpufreq driver that will also change policies during CPUFREQ_ADJUST,
> > once the request comes from the underlying FW so there would be a fight
> > who gets there first since cpu_cooling will change the policy in
> > CPUFREQ_ADJUST notifier_chain and the driver would do the same thing.
Okay, I had a detailed look this morning. cpufreq-notifier is designed
this way that policy->max can be updated by drivers.. So, that's fine.
Now coming to your problem. So, there are two users: fw and thermal,
which can affect policy->max. Now, both of them need to respect the
limits set by others and only decrease policy->max from the notifier
if it doesn't suit them.
I think it should work pretty well, unless you know you have triggered
a corner case somewhere, that I am not able to imagine.
Please let me know in case I am wrong.
--
viresh
next prev parent reply other threads:[~2015-08-03 3:13 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-21 22:13 [PATCH] thermal/cpu_cooling: remove local cooling state variable Radivoje Jovanovic
2015-07-24 15:26 ` Punit Agrawal
2015-07-24 17:09 ` Radivoje Jovanovic
2015-07-29 16:46 ` Punit Agrawal
2015-07-29 17:00 ` Radivoje Jovanovic
2015-07-30 8:05 ` Viresh Kumar
2015-07-30 20:21 ` Radivoje Jovanovic
2015-07-31 3:18 ` Viresh Kumar
2015-07-31 15:30 ` Radivoje Jovanovic
2015-08-01 11:34 ` Viresh Kumar
2015-08-03 3:13 ` Viresh Kumar [this message]
2015-08-03 19:28 ` Radivoje Jovanovic
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