Date:   Tue, 27 Oct 2020 10:19:12 +0100
From:   Elia Devito <eliadevito@...il.com>
To:     Mark Pearson <markpearson@...ovo.com>,
        Hans de Goede <hdegoede@...hat.com>
Cc:     dvhart@...radead.org, mgross@...ux.intel.com,
        mario.limonciello@...l.com, hadess@...ess.net, bberg@...hat.com,
        linux-pm@...r.kernel.org, linux-acpi@...r.kernel.org,
        platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [External] Re: [PATCH] [RFC] Documentation: Add documentation for new platform_profile sysfs attribute

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@...hat.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@...hat.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@...hat.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

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