linux-kernel - Re: [PATCH v2 1/1] ACPI: platform_profile: Treat quiet and low power the same

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Message-ID: <CAJZ5v0hNHFLtBwTTuPc7mNZhCKkmFJgFwgw88_BR_7nQ+rc6Cw@mail.gmail.com>
Date: Tue, 4 Mar 2025 15:58:55 +0100
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Mario Limonciello <superm1@...nel.org>, Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc: Antheas Kapenekakis <lkml@...heas.dev>, Kurt Borja <kuurtb@...il.com>, 
	Shyam Sundar S K <Shyam-sundar.S-k@....com>, Hans de Goede <hdegoede@...hat.com>, 
	"Luke D . Jones" <luke@...nes.dev>, Mark Pearson <mpearson-lenovo@...ebb.ca>, 
	"open list:AMD PMF DRIVER" <platform-driver-x86@...r.kernel.org>, 
	open list <linux-kernel@...r.kernel.org>, 
	"open list:ACPI" <linux-acpi@...r.kernel.org>, "Derek J . Clark" <derekjohn.clark@...il.com>, 
	me@...egospodneti.ch, Denis Benato <benato.denis96@...il.com>, 
	Mario Limonciello <mario.limonciello@....com>
Subject: Re: [PATCH v2 1/1] ACPI: platform_profile: Treat quiet and low power
 the same

On Tue, Mar 4, 2025 at 3:52 PM Mario Limonciello <superm1@...nel.org> wrote:
>
> On 3/4/2025 08:08, Rafael J. Wysocki wrote:
> > On Tue, Mar 4, 2025 at 1:49 PM Mario Limonciello <superm1@...nel.org> wrote:
> >>
> >> On 3/4/25 02:38, Antheas Kapenekakis wrote:
> >>> On Tue, 4 Mar 2025 at 07:48, Mario Limonciello <superm1@...nel.org> wrote:
> >>>>
> >>>> From: Mario Limonciello <mario.limonciello@....com>
> >>>>
> >>>> When two drivers don't support all the same profiles the legacy interface
> >>>> only exports the common profiles.
> >>>>
> >>>> This causes problems for cases where one driver uses low-power but another
> >>>> uses quiet because the result is that neither is exported to sysfs.
> >>>>
> >>>> If one platform profile handler supports quiet and the other
> >>>> supports low power treat them as the same for the purpose of
> >>>> the sysfs interface.
> >>>>
> >>>> Fixes: 688834743d67 ("ACPI: platform_profile: Allow multiple handlers")
> >>>> Reported-by: Antheas Kapenekakis <lkml@...heas.dev>
> >>>> Closes: https://lore.kernel.org/platform-driver-x86/e64b771e-3255-42ad-9257-5b8fc6c24ac9@gmx.de/T/#mc068042dd29df36c16c8af92664860fc4763974b
> >>>> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
> >>>> ---
> >>>>    drivers/acpi/platform_profile.c | 38 ++++++++++++++++++++++++++++++---
> >>>>    1 file changed, 35 insertions(+), 3 deletions(-)
> >>>>
> >>>> diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/platform_profile.c
> >>>> index 2ad53cc6aae53..d9a7cc5891734 100644
> >>>> --- a/drivers/acpi/platform_profile.c
> >>>> +++ b/drivers/acpi/platform_profile.c
> >>>> @@ -73,8 +73,20 @@ static int _store_class_profile(struct device *dev, void *data)
> >>>>
> >>>>           lockdep_assert_held(&profile_lock);
> >>>>           handler = to_pprof_handler(dev);
> >>>> -       if (!test_bit(*bit, handler->choices))
> >>>> -               return -EOPNOTSUPP;
> >>>> +       if (!test_bit(*bit, handler->choices)) {
> >>>> +               switch (*bit) {
> >>>> +               case PLATFORM_PROFILE_QUIET:
> >>>> +                       *bit = PLATFORM_PROFILE_LOW_POWER;
> >>>> +                       break;
> >>>> +               case PLATFORM_PROFILE_LOW_POWER:
> >>>> +                       *bit = PLATFORM_PROFILE_QUIET;
> >>>> +                       break;
> >>>> +               default:
> >>>> +                       return -EOPNOTSUPP;
> >>>> +               }
> >>>> +               if (!test_bit(*bit, handler->choices))
> >>>> +                       return -EOPNOTSUPP;
> >>>> +       }
> >>>>
> >>>>           return handler->ops->profile_set(dev, *bit);
> >>>>    }
> >>>> @@ -252,8 +264,16 @@ static int _aggregate_choices(struct device *dev, void *data)
> >>>>           handler = to_pprof_handler(dev);
> >>>>           if (test_bit(PLATFORM_PROFILE_LAST, aggregate))
> >>>>                   bitmap_copy(aggregate, handler->choices, PLATFORM_PROFILE_LAST);
> >>>> -       else
> >>>> +       else {
> >>>> +               /* treat quiet and low power the same for aggregation purposes */
> >>>> +               if (test_bit(PLATFORM_PROFILE_QUIET, handler->choices) &&
> >>>> +                   test_bit(PLATFORM_PROFILE_LOW_POWER, aggregate))
> >>>> +                       set_bit(PLATFORM_PROFILE_QUIET, aggregate);
> >>>> +               else if (test_bit(PLATFORM_PROFILE_LOW_POWER, handler->choices) &&
> >>>> +                        test_bit(PLATFORM_PROFILE_QUIET, aggregate))
> >>>> +                       set_bit(PLATFORM_PROFILE_LOW_POWER, aggregate);
> >>>>                   bitmap_and(aggregate, handler->choices, aggregate, PLATFORM_PROFILE_LAST);
> >>>> +       }
> >>>
> >>> So you end up showing both? If that's the case, isn't it equivalent to
> >>> just make amd-pmf show both quiet and low-power?
> >>>
> >>> I guess it is not ideal for framework devices. But if asus devices end
> >>> up showing both, then it should be ok for framework devices to show
> >>> both.
> >>>
> >>> I like the behavior of the V1 personally.
> >>
> >> No; this doesn't cause it to show both.  It only causes one to show up.
> >
> > Which may not be the one that was shown before IIUC and that's not good.
> >
> > What actually is the problem with the previous version?
>
> Functionally?  Nothing.  This was to demonstrate the other way to do it
> that I preferred and get feedback on it as an alternative.
>
> If you and Ilpo are happy with v1 that's totally fine and we can go with
> that.

I'd prefer to go for the v1 at this point because it fixes a
regression affecting user space that needs to be addressed before the
6.14 release (and there is not too much time left) and it has been
checked on the affected systems.

Ilpo, do you agree?