linux-kernel - Re: [PATCH 1/2] thermal: cooling: Check Energy Model type in cpufreq_cooling and devfreq

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Message-ID: <211a3606-2f4c-227b-33aa-177ef68a49a3@arm.com>
Date:   Tue, 22 Feb 2022 17:05:13 +0000
From:   Lukasz Luba <lukasz.luba@....com>
To:     daniel.lezcano@...aro.org
Cc:     amit.kachhap@...il.com, viresh.kumar@...aro.org, rafael@...nel.org,
        amitk@...nel.org, rui.zhang@...el.com, dietmar.eggemann@....com,
        Pierre.Gondois@....com, Matthias Kaehlcke <mka@...omium.org>,
        Doug Anderson <dianders@...omium.org>,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] thermal: cooling: Check Energy Model type in
 cpufreq_cooling and devfreq_cooling

Hi Daniel,

gentle ping

On 2/17/22 18:18, Lukasz Luba wrote:
> Hi Daniel,
> 
> 
> On 2/7/22 7:30 AM, Lukasz Luba wrote:
>> The Energy Model supports power values either in Watts or in some 
>> abstract
>> scale. When the 2nd option is in use, the thermal governor IPA should not
>> be allowed to operate, since the relation between cooling devices is not
>> properly defined. Thus, it might be possible that big GPU has lower power
>> values in abstract scale than a Little CPU. To mitigate a misbehaviour
>> of the thermal control algorithm, simply not register a cooling device
>> capable of working with IPA.
>>
>> Signed-off-by: Lukasz Luba <lukasz.luba@....com>
>> ---
>>   drivers/thermal/cpufreq_cooling.c |  2 +-
>>   drivers/thermal/devfreq_cooling.c | 16 +++++++++++++---
>>   2 files changed, 14 insertions(+), 4 deletions(-)
> 
> The discussion in below this patch went slightly off-topic but it was
> valuable. It clarified also there are no broken platforms with this
> change.
> 
> Could you take the patch into the thermal tree, please?
> 
> Regards,
> Lukasz