Re: [PATCH 8/8] cpufreq: vexpress: Use auto-registration for energy model

From: Lukasz Luba <lukasz.luba@arm.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Rafael Wysocki <rjw@rjwysocki.net>,
	Vincent Donnefort <vincent.donnefort@arm.com>,
	Sudeep Holla <sudeep.holla@arm.com>,
	linux-pm@vger.kernel.org,
	Vincent Guittot <vincent.guittot@linaro.org>,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 8/8] cpufreq: vexpress: Use auto-registration for energy model
Date: Tue, 10 Aug 2021 11:11:31 +0100	[thread overview]
Message-ID: <2210acb9-2666-7aa9-d36c-346480541f3c@arm.com> (raw)
In-Reply-To: <20210810100652.h473q6hgtc5czfyk@vireshk-i7>

On 8/10/21 11:06 AM, Viresh Kumar wrote:
> On 10-08-21, 11:05, Lukasz Luba wrote:
>> I can see that this driver calls explicitly the
>> of_cpufreq_cooling_register()
>> It does this in the cpufreq_driver->ready() callback
>> implementation: ve_spc_cpufreq_ready()
>>
>> With that in mind, the new code in the patch 1/8, which
>> registers the EM, should be called even earlier, above:
>> ---------------------8<---------------------------------
>> /* Callback for handling stuff after policy is ready */
>> 	if (cpufreq_driver->ready)
>> 		cpufreq_driver->ready(policy);
>> ------------------->8----------------------------------
> 
> Thanks. I will look at this sequencing issue again.
> 
>> This also triggered a question:
>> If this new flag can be set in the cpufreq driver which hasn't set
>> CPUFREQ_IS_COOLING_DEV
>> ?
> 
> Why not ?

I thought someone could try to call cpufreq_cooling_register()
from the cpufreq driver init function, but it's not possible. I have
just checked that, so should be good with these two flags being
independent and working fine.

> 
>> I can only see one driver (this one in the patch) which has such
>> configuration.
> 