linux-kernel - Re: [PATCH v3 1/3] acpi: platform_profile

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Message-ID: <278FC60D-C084-44B9-A0DB-23FAC930458B@gmail.com>
Date: Thu, 27 Nov 2025 06:36:02 -0800
From: "Derek J. Clark" <derekjohn.clark@...il.com>
To: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
 Armin Wolf <W_Armin@....de>
CC: Len Brown <lenb@...nel.org>, "Rafael J . Wysocki" <rafael@...nel.org>,
 Jonathan Corbet <corbet@....net>, Mario Limonciello <superm1@...nel.org>,
 Zhixin Zhang <zhangzx36@...ovo.com>, Mia Shao <shaohz1@...ovo.com>,
 Mark Pearson <mpearson-lenovo@...ebb.ca>,
 "Pierre-Loup A . Griffais" <pgriffais@...vesoftware.com>,
 Kurt Borja <kuurtb@...il.com>, platform-driver-x86@...r.kernel.org,
 linux-doc@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>,
 linux-acpi@...r.kernel.org
Subject: Re: [PATCH v3 1/3] acpi: platform_profile - Add max-power profile option

On November 27, 2025 4:11:36 AM PST, "Ilpo Järvinen" <ilpo.jarvinen@...ux.intel.com> wrote:
>On Mon, 17 Nov 2025, Armin Wolf wrote:
>
>> Am 16.11.25 um 20:01 schrieb Derek J. Clark:
>> 
>> > On November 16, 2025 8:13:17 AM PST, Armin Wolf <W_Armin@....de> wrote:
>> > > Am 13.11.25 um 22:26 schrieb Derek J. Clark:
>> > > 
>> > > > Some devices, namely Lenovo Legion devices, have an "extreme" mode where
>> > > > power draw is at the maximum limit of the cooling hardware. Add a new
>> > > > "max-power" platform profile to properly reflect this operating mode.
>> > > > 
>> > > > Reviewed-by: Mario Limonciello (AMD) <superm1@...nel.org>
>> > > > Acked-by: Rafael J. Wysocki (Intel) <rafael@...nel.org>
>> > > > Signed-off-by: Derek J. Clark <derekjohn.clark@...il.com>
>> > > > ---
>> > > >    Documentation/ABI/testing/sysfs-class-platform-profile | 2 ++
>> > > >    drivers/acpi/platform_profile.c                        | 1 +
>> > > >    include/linux/platform_profile.h                       | 1 +
>> > > >    3 files changed, 4 insertions(+)
>> > > > 
>> > > > diff --git a/Documentation/ABI/testing/sysfs-class-platform-profile
>> > > > b/Documentation/ABI/testing/sysfs-class-platform-profile
>> > > > index dc72adfb830a..fcab26894ec3 100644
>> > > > --- a/Documentation/ABI/testing/sysfs-class-platform-profile
>> > > > +++ b/Documentation/ABI/testing/sysfs-class-platform-profile
>> > > > @@ -23,6 +23,8 @@ Description:	This file contains a space-separated
>> > > > list of profiles supported
>> > > >    					power consumption with a
>> > > > slight bias
>> > > >    					towards performance
>> > > >    		performance		High performance operation
>> > > > +		max-power		Higher performance operation that may
>> > > > exceed
>> > > > +					internal battery draw limits when on
>> > > > AC power
>> > > I am not sure if it is a good idea to allow platform_profile_cycle() to
>> > > cycle into this
>> > > new max-power profile. The system could encounter a brownout if it is
>> > > currently operating
>> > > on battery power when selecting max-power.
>> > > 
>> > > Maybe we should prevent platform_profile_cylce() from selecting max-power?
>> > At least for Lenovo devices unplugging AC will automatically throttle the
>> > ppt values to roughly equivalent to performance. It will look at a different
>> > WMI data block for the values when switched, so there's no risk for cycling
>> > in this case. This seems like smart hardware design, but we've certainly
>> > seen bad hardware design so the concern is warranted. Perhaps it is worth
>> > visiting if another vendor implements it differently? That being said, what
>> > you're describing would match up with how the physical profile selection
>> > button works, so it would align with consumer expectation. I have no strong
>> > feelings either way, but I'm a little concerned about meeting the merge
>> > window as this series fixes a pretty disruptive bug affecting 6.17 users.
>> > 
>> > Regards,
>> > - Derek
>> > 
>> If the physical platform selection button does not automatically select the
>> max-power profile under Windows, then we should copy this behavior i think.
>> The changes necessary for that are fairly small, basically you only have to
>> extend the handling of PLATFORM_PROFILE_CUSTOM inside platform_profile_cycle()
>> to also include the max-power profile. So i would prefer if we modify
>> platform_profile_cycle() now has doing this later might be seen as a
>> regression.
>
>Derek,
>
>Any comments on this?
>
>I'd very much prefer to take this series in this cycle but this comment 
>seems unresolved and has userspace visible impact so may bind us 
>irrevocably to certain behavior.
>
>--
> i.

Ilpo,

If I'm being totally honest I forgot about this request. I can knock this out pretty quickly and send v4 today.

Thanks,
Derek
>> 
>> Thanks,
>> Armin Wolf
>> 
>> > > Other than that:
>> > > Reviewed-by: Armin Wolf <W_Armin@....de>
>> > > 
>> > > >    		custom			Driver defined custom profile
>> > > >    		====================
>> > > > ========================================
>> > > >    diff --git a/drivers/acpi/platform_profile.c
>> > > > b/drivers/acpi/platform_profile.c
>> > > > index b43f4459a4f6..aa1dce05121b 100644
>> > > > --- a/drivers/acpi/platform_profile.c
>> > > > +++ b/drivers/acpi/platform_profile.c
>> > > > @@ -37,6 +37,7 @@ static const char * const profile_names[] = {
>> > > >    	[PLATFORM_PROFILE_BALANCED] = "balanced",
>> > > >    	[PLATFORM_PROFILE_BALANCED_PERFORMANCE] =
>> > > > "balanced-performance",
>> > > >    	[PLATFORM_PROFILE_PERFORMANCE] = "performance",
>> > > > +	[PLATFORM_PROFILE_MAX_POWER] = "max-power",
>> > > >    	[PLATFORM_PROFILE_CUSTOM] = "custom",
>> > > >    };
>> > > >    static_assert(ARRAY_SIZE(profile_names) == PLATFORM_PROFILE_LAST);
>> > > > diff --git a/include/linux/platform_profile.h
>> > > > b/include/linux/platform_profile.h
>> > > > index a299225ab92e..855b28340e95 100644
>> > > > --- a/include/linux/platform_profile.h
>> > > > +++ b/include/linux/platform_profile.h
>> > > > @@ -24,6 +24,7 @@ enum platform_profile_option {
>> > > >    	PLATFORM_PROFILE_BALANCED,
>> > > >    	PLATFORM_PROFILE_BALANCED_PERFORMANCE,
>> > > >    	PLATFORM_PROFILE_PERFORMANCE,
>> > > > +	PLATFORM_PROFILE_MAX_POWER,
>> > > >    	PLATFORM_PROFILE_CUSTOM,
>> > > >    	PLATFORM_PROFILE_LAST, /*must always be last */
>> > > >    };
>> > 
>>