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

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Message-ID: <4e090ffe-c19b-8e2c-0396-72dc33361f35@arm.com>
Date:   Thu, 17 Feb 2022 18:18:29 +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,


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