Re: [PATCHv9 02/20] thermal: introduce device tree parser

[Eduardo Valentin]

On 06-01-2014 09:51, Mark Rutland wrote:
> On Thu, Jan 02, 2014 at 05:50:06PM +0000, Matthew Longnecker wrote:
>>
>>> I think the platform driver may set governor for the thermal zone,
>>> so how about to add a property named as "governor",
>>> and parse it to tzp->governor_name,
>>> something like:
>>>                  ret = of_property_read_string(child, "governor", &str);
>>>                  if (ret == 0)
>>>                          if (strlen(str) < THERMAL_NAME_LENGTH)
>>>                                  strcpy(tzp->governor_name, str);
>>>
>>> Thanks.
>>> Wei.
>>
>> DT is supposed to describe the hardware, right? The governor isn't 
>> hardware -- it's a software control policy. On the other hand, that 
>> control policy must be tuned according to the behaviors of the platform 
>> hardware otherwise the system will be unstable.
>>
>> Is it appropriate to be naming the governor in DT? If so, is it equally 
>> appropriate to describe any governor-specific parameters in DT (even 
>> though they are pure software constructs)?
> 
> The dt should be relatively static -- if the hardware doesn't change the
> dt shouldn't have to.
> 
> The governers are not static. We can introduce new ones and throw away
> old ones at any time. Tuning parameters can also change at any time.
> 
> I'd prefer to not have governer details described in the dt, and the
> choice of governer and configuration of its tuning parameters should be
> made at runtime somehow.

Agreed.

> 
> Thanks,
> Mark.
> 
> 


-- 
You have got to be excited about what you are doing. (L. Lamport)

Eduardo Valentin

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