linux-kernel - Re: [PATCH V3] thermal/core/power_allocator: avoid thermal cdev can not be reset

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Message-ID: <e31da1fa-168d-9a85-cdb3-66192d887d83@arm.com>
Date:   Fri, 14 Apr 2023 15:18:34 +0100
From:   Lukasz Luba <lukasz.luba@....com>
To:     Daniel Lezcano <daniel.lezcano@...aro.org>
Cc:     Di Shen <di.shen@...soc.com>, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org, xuewen.yan@...soc.com,
        jeson.gao@...soc.com, zhanglyra@...il.com, orsonzhai@...il.com,
        rui.zhang@...el.com, amitk@...nel.org, rafael@...nel.org,
        Di Shen <cindygm567@...il.com>
Subject: Re: [PATCH V3] thermal/core/power_allocator: avoid thermal cdev can
 not be reset



On 4/14/23 12:12, Daniel Lezcano wrote:
> On 13/04/2023 10:40, Di Shen wrote:
>> We have discussed this question in patch-v1:
>> https://lore.kernel.org/all/f6aaa5f1-495d-a158-14d8-ddb2bffbd9c2@arm.com/
>>
>> Simply put, we use the trip_temp in the Android System; set different
>> trip_temp for thermal control of different scenarios.
> 
> The changes are dealing with the trip points and trying to detect the 
> threshold. That part should be handled in the thermal core or thermal 
> trip side, not in the governor.
> 
> AFAICT, if a trip point is changed, then the power allocator should be 
> reset, including the cdev state.
> 
> It would be more convenient to add an ops to the governor ops structure 
> to reset the governor and then call it when a trip point is changed in 
> thermal_zone_set_trip()
> 
> 

Sounds reasonable to have a proper API and fwk handling this corner
case scenario.
Although, if there is a need for a 'easy-to-backport' fix for IPA only,
I agree with this patch, since it's straight forward to put in some
Android kernel. We can later fix the framework to handle this properly.
Anyway, both ways are OK to me.

Regards,
Lukasz