Re: community PM requirements/issues and PowerOP [Was: Re: So, what's the status on the recent patches here?]

["Eugeny S. Mints" <eugeny.mints@gmail.com>]

Pavel Machek wrote:
> Hi!
> 
>>>>>> Are you arguing that the cpufreq interface be morphed to support power
>>>>>> op applications?
>>>>> No. I'm arguing that
>>>>>
>>>>> * cpufreq interface should be used for changing cpu frequency
>>>> the patch set i sent out has cpufreq used for changing cpu frequency,
>>>> hasn't it?
>>> I was talking about kernel<->user interface.
>> me too. PowerOP is inkernel interface but which _allows_ to build various
>> different kernel<->user interfaces on top of it. This PowerOP _advantage_ 
>> allows community to experiment with various kernel<->user interfaces
>> on top 
> 
> Kernel interface is not something to be experimented with.
it is since current interface (cpufreq in conjunction with /sys/power/state, 
etc) does not address all requirements to the interface. PowerOP approach helps 
to figure out best interface gracefully since there is no common opinion in the 
community yet.
> 
>> and eventually end up with the best solution. The solution can be either 
>> one universal, agreed by community kernel<-> user interface on top or I can 
>> imaging the approach when kernel<-> user interfaces on top are configurable 
>> feature and system designer choses kernel<->user interface which fits best 
>> the systems he/she builds.
> 
> ...and configurable kernel interfaces are very bad idea.
it's not an argument. the ideal goal to end up with one universal interface. but 
until you personally stuck with cpufreq interface this is the only way to 
proceed towards universal interface design. let people to investigate advantages 
and disadvantages of this and that interfaces on a working system since we can't 
convince each other by this flame.
> 
>>> You did echo low > something to change CPU frequency, IIRC.
>> My patch set presents two different interfaces built on top of PowerOP - 
>> cpufreq and sysfs interfaces. So _no_, PowerOP is not all about
> 
> Okay, drop sysfs interface, and we may have something that can be
> reviewed.
previous take of PowerOP did not contain sysfs part but I have not received any 
you comment on this. Sysfs is completely optional feature after all.
 >
> Actually that's good idea. Submit powerop without doing _any_ kernel
> interface changes, so we can see that it makes sense...
It was submitted this way several times.

Eugeny