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

[Daniel Lezcano]

On 14/04/2023 16:18, Lukasz Luba wrote:
> 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@xxxxxxx/
> > >
> > > 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.

Unfortunately, we can not do the maintenance of the Linux kernel based 
on an 'easy-to-backport' policy to Android.

This patch could be applied from-list to Android as a hotfix. But for 
Linux the fix should be more elaborated. One solution is to add a 
'reset' ops and call it from the trip point update function.

Did you double check the issue is not impacting the other governors too ?


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