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Subject: Re: [External] Re: [PATCH] [RFC] Documentation: Add documentation for
 new platform_profile sysfs attribute
To:     Elia Devito <eliadevito@gmail.com>,
        Hans de Goede <hdegoede@redhat.com>
CC:     <dvhart@infradead.org>, <mgross@linux.intel.com>,
        <mario.limonciello@dell.com>, <hadess@hadess.net>,
        <bberg@redhat.com>, <linux-pm@vger.kernel.org>,
        <linux-acpi@vger.kernel.org>,
        <platform-driver-x86@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
References: <markpearson@lenovo.com>
 <ef9b93a0-636f-9b96-9d5b-fee1e5738af7@lenovo.com>
 <1fbaf1fa-47c6-afe7-ca9e-41b3ad6a4556@redhat.com> <12633630.uLZWGnKmhe@pce>
From:   Mark Pearson <markpearson@lenovo.com>
Message-ID: <1bddcede-5e12-6089-8920-26dd5f534b44@lenovo.com>
Date:   Tue, 27 Oct 2020 08:28:54 -0400
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Hi Elia

On 27/10/2020 05:19, Elia Devito wrote:
> Hi to all,
> 
> In data martedì 27 ottobre 2020 08:54:44 CET, Hans de Goede ha scritto:
>> Hi,
>>
>> On 10/26/20 8:55 PM, Mark Pearson wrote:
>>> Thanks Hans
>>>
>>> On 26/10/2020 14:33, Hans de Goede wrote:
>>>> Hi Mark,
>>>>
>>>> Thank you for this new version.
>>>>
>>>> On 10/26/20 6:44 PM, Mark Pearson wrote:
>>>>> From: Hans de Goede <hdegoede@redhat.com>
>>>
>>> <snip>
>>>
>>>>> +
>>>>> +If for some reason there is no good match when mapping then a new
>>>>> profile-name +may be added. Drivers which wish to introduce new
>>>>> profile-names must: +1. Have very good reasons to do so.
>>>>> +2. Add the new profile-name to this document, so that future drivers
>>>>> which also +   have a similar problem can use the same new.
>>>>
>>>> s/same new/same name/
>>>
>>> I've read this document so many times...I'm not sure how I missed that
>>> one. Thanks.>
>>>>> + Usually new profile-names will
>>>>> +   be added to the "extra profile-names" section of this document. But
>>>>> in some +   cases the set of standard profile-names may be extended.
>>>>
>>>> With the change from a more generic API to this new one more targeted
>>>> towards DPTF I would drop this part.
>>>
>>> OK - I have some questions then related to this change, below
>>>
>>>>> +
>>>>> +What:        /sys/firmware/acpi/platform_profile_choices
>>>>> +Date:        October 2020
>>>>> +Contact:    Hans de Goede <hdegoede@redhat.com>
>>>>> +Description:
>>>>> +        Reading this file gives a space separated list of profiles
>>>>> +        supported for this device.
>>>>> +
>>>>> +        Drivers must use the following standard profile-names whenever
>>>>> +        possible:
>>>>> +
>>>>> +        low-power:        Emphasises low power consumption
>>>>> +        quiet:            Offers quieter operation (lower fan
>>>>> +                    speed but with higher performance and
>>>>> +                    temperatures then seen in low-power
>>>>
>>>> I think the description here is a bit too specific, this may cause
>>>> userspace to have expectations which are not necessary true. I would
>>>> describe this as just:
>>>>
>>>>          quiet:            Emphasises quieter operation
>>>
>>> Agreed. I'll update
>>>
>>>>> +        balanced:        Balance between low power consumption
>>>>> +                    and performance
>>>>> +        performance:        Emphasises performance (and may lead to
>>>>> +                    higher temperatures and fan speeds)
>>>>> +
>>>>> +        Userspace may expect drivers to offer at least several of these
>>>>> +        standard profile-names! If none of the above are a good match
>>>>> +        for some of the drivers profiles, then drivers may use one of
>>>>> +        these extra profile-names:
>>>>> +        <reserved for future use>
>>>>> +
>>>
>>> If we remove the extra profile-names section above then I think it should
>>> be removed here too. If someone wants to add a new 'mode' then it would
>>> be added to the list of 'standard names', and becomes a new option.
>>> Wanted to check I'm not missing something important.
>> You are completely right, any references to an extra profile-names section
>> should be removed here too. I did intend to add that it should be removed
>> here too, but I forgot.
>>
>>>>> +What:        /sys/firmware/acpi/platform_profile
>>>>> +Date:        October 2020
>>>>> +Contact:    Hans de Goede <hdegoede@redhat.com>
>>>>> +Description:
>>>>> +        Reading this file gives the current selected profile for this
>>>>> +        device. Writing this file with one of the strings from
>>>>> +        available_profiles changes the profile to the new value.
>>>>
>>>> The part about custom profiles below may be dropped. That was intended
>>>> for use with e.g. GPUs but since this now strictly is a system-level
>>>> profile API, the part below can be dropped now.
>>>
>>> Agreed
>>>
>>>>> +
>>>>> +        Reading this file may also return "custom". This is intended
>>>>> for
>>>>> +        drivers which have and export multiple knobs. Such drivers may
>>>>> +        very well still want to offer a set of profiles for easy of use
>>>>> +        and to be able to offer a consistent standard API (this API) to
>>>>> +        userspace for configuring their performance. The "custom" value
>>>>> +        is intended for when ai user has directly configured the knobs
>>>>> +        (through e.g. some advanced control-panel for a GPU) and the
>>>>> +        knob values do not match any of the presets represented by the
>>>>> +        platform-profiles. In this case writing this file will
>>>>> +        override the modifications and restore the selected presets.
>>>>> +
>>>>
>>>> Regards,
>>>>
>>>> Hans
>>>
>>> Thanks!
>>> mark
>>
>> Regards,
>>
>> Hans
> 
> This look good,
> only thing is that hp-wmi driver need a cool profile (Emphasises the computer
> cool to touch), if you can add it would be perfect.
> 
> Regards
> Elia
> 
> 
> 
Is low-power is different to cool? I figured low-power was going to be 
cool so combined them.
I could call it low-power-cool if that helps? It seems a little clunky 
but not too bad. I'm sure the user space folks can put sunglasses on it 
or something ;)

Mark