RE: [PATCH] of: thermal: Fixed governor at each thermal zone

[êìí/ìììêì/SW Platform(ì)AOTí(hugh.kang@lge.com)]

Hello Rui, Javi, Lukasz and Eduardo

> -----Original Message-----
> From: Zhang Rui [mailto:rui.zhang@xxxxxxxxx]
> Sent: Wednesday, September 28, 2016 10:31 AM
> To: Eduardo Valentin; Lukasz Luba
> Cc: Inhyuk Kang; linux-pm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH] of: thermal: Fixed governor at each thermal zone
> 
> Hi, Javi, Lukasz and Eduardo,
> 
> thanks for your input.
> 
> thanks,
> rui
> 
> On ä, 2016-09-27 at 06:22 -0700, Eduardo Valentin wrote:
> > Hello, Lukasz, Inhyuk, Javi,
> >
> > On Tue, Sep 27, 2016 at 12:52:04PM +0100, Lukasz Luba wrote:
> > >
> > >
> > > On 27/09/16 02:46, Zhang Rui wrote:
> > > >
> > > > On ä, 2016-09-19 at 10:18 +0900, Inhyuk Kang wrote:
> > > > >
> > > > > It is necessary to be added governor at each thermal_zone.
> > > > > Because some governors should be operated in the during the
> > > > > kernel booting in order to avoid heating problem.
> > > > >
> > > > > Default governor cannot be covered all thermal zones policy
> > > > > because some thermal zones want to apply different one.
> > > > > For example, the power allocator governor operates differently
> > > > > with step wise governor.
> > > > > Hence, it is better to parse governor parameter from the device
> > > > > tree.
> > > > >
> > > > > Signed-off-by: Inhyuk Kang <hugh.kang@xxxxxxx>
> > > > >
> > > > The patch looks okay to me.
> > > > Eduardo, what do you think of this patch?
> > > Hi Rui,
> > >
> > > Beside the fact which Javi pointed out in his email, there is an
> > > issue in the patch itself.
> > > The idea behind the patch is good, but the patch should have some
> > > improvements, i.e:
> > > - strncpy instead of strcpy,
> > > - if the governor name is not found in the registered governor's
> > > list by __find_governor (and then null is set) we should probably
> > > switch to default governor,
> > > - add DT documentation,
> > Also, the idea of the patch is good, almost tempting to do it, but
> > unfortunately, not acceptable from DT perspective. The patch infringes
> > two of the DT conceptual and design decision of:
> > (a) DT should describe hardware, not policy;
> > (b) DT should describe hardware, not OS specific implementations.
> >
> > As already pointed by Javi, this patch has already been proposed (more
> > than one time by different people), but, it still continues to be
> > unacceptable.
> >
> > Cheers,
> >
> >
> > >
> > >
> > > Regards,
> > > Lukasz
> > >
Thank you for reviewing this patch. I understand your ideas. 
During the thermal testing into device, the thermal policy should be applied in the begging of kernel boot sometimes.
Hence, I have suggested above solution.

Anyway, the DT perspective like above, this patch is better not to be upstream.

Thank you very much.

Regards,
Hugh Kang

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