Re: [PATCH 1/2] thermal: cooling: Check Energy Model type in cpufreq_cooling and devfreq_cooling

From: Lukasz Luba <lukasz.luba@arm.com>
To: daniel.lezcano@linaro.org
Cc: amit.kachhap@gmail.com, viresh.kumar@linaro.org,
	rafael@kernel.org, amitk@kernel.org, rui.zhang@intel.com,
	dietmar.eggemann@arm.com, Pierre.Gondois@arm.com,
	Matthias Kaehlcke <mka@chromium.org>,
	Doug Anderson <dianders@chromium.org>,
	linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] thermal: cooling: Check Energy Model type in cpufreq_cooling and devfreq_cooling
Date: Thu, 17 Feb 2022 18:18:29 +0000	[thread overview]
Message-ID: <4e090ffe-c19b-8e2c-0396-72dc33361f35@arm.com> (raw)
In-Reply-To: <20220207073036.14901-2-lukasz.luba@arm.com>

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@arm.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