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

From: Daniel Lezcano
Date: Tue Feb 22 2022 - 13:12:44 EST



Hi Lukasz,

I don't think it makes sense to remove the support of the energy model if the units are abstracts.

IIUC, regarding your previous answer, we don't really know what will do the SoC vendor with these numbers and likely they will provide consistent abstract values which won't prevent a correct behavior.

What would be the benefit of giving inconsistent abstract values which will be unusable except of giving a broken energy model?

Your proposed changes would be acceptable if the energy model has a broken flag IMO

On 22/02/2022 18:05, Lukasz Luba wrote:
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@xxxxxxx>
---
  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


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