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From:   Elia Devito <eliadevito@gmail.com>
To:     Mark Pearson <markpearson@lenovo.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
Subject: Re: [External] Re: [PATCH] [RFC] Documentation: Add documentation for new platform_profile sysfs attribute
Date:   Tue, 27 Oct 2020 10:19:12 +0100
Message-ID: <12633630.uLZWGnKmhe@pce>
In-Reply-To: <1fbaf1fa-47c6-afe7-ca9e-41b3ad6a4556@redhat.com>
References: <markpearson@lenovo.com> <ef9b93a0-636f-9b96-9d5b-fee1e5738af7@lenovo.com> <1fbaf1fa-47c6-afe7-ca9e-41b3ad6a4556@redhat.com>
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Hi to all,

In data marted=EC 27 ottobre 2020 08:54:44 CET, Hans de Goede ha scritto:
> Hi,
>=20
> On 10/26/20 8:55 PM, Mark Pearson wrote:
> > Thanks Hans
> >=20
> > On 26/10/2020 14:33, Hans de Goede wrote:
> >> Hi Mark,
> >>=20
> >> Thank you for this new version.
> >>=20
> >> On 10/26/20 6:44 PM, Mark Pearson wrote:
> >>> From: Hans de Goede <hdegoede@redhat.com>
> >=20
> > <snip>
> >=20
> >>> +
> >>> +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.
> >>=20
> >> s/same new/same name/
> >=20
> > I've read this document so many times...I'm not sure how I missed that
> > one. Thanks.>=20
> >>> + Usually new profile-names will
> >>> +   be added to the "extra profile-names" section of this document. B=
ut
> >>> in some +   cases the set of standard profile-names may be extended.
> >>=20
> >> With the change from a more generic API to this new one more targeted
> >> towards DPTF I would drop this part.
> >=20
> > OK - I have some questions then related to this change, below
> >=20
> >>> +
> >>> +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 whenev=
er
> >>> +        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
> >>=20
> >> 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:
> >>=20
> >>         quiet:            Emphasises quieter operation
> >=20
> > Agreed. I'll update
> >=20
> >>> +        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 th=
ese
> >>> +        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>
> >>> +
> >=20
> > If we remove the extra profile-names section above then I think it shou=
ld
> > 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.
>=20
> >>> +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.
> >>=20
> >> 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.
> >=20
> > Agreed
> >=20
> >>> +
> >>> +        Reading this file may also return "custom". This is intended
> >>> for
> >>> +        drivers which have and export multiple knobs. Such drivers m=
ay
> >>> +        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" va=
lue
> >>> +        is intended for when ai user has directly configured the kno=
bs
> >>> +        (through e.g. some advanced control-panel for a GPU) and the
> >>> +        knob values do not match any of the presets represented by t=
he
> >>> +        platform-profiles. In this case writing this file will
> >>> +        override the modifications and restore the selected presets.
> >>> +
> >>=20
> >> Regards,
> >>=20
> >> Hans
> >=20
> > Thanks!
> > mark
>=20
> Regards,
>=20
> Hans

This look good,
only thing is that hp-wmi driver need a cool profile (Emphasises the comput=
er=20
cool to touch), if you can add it would be perfect.

Regards
Elia