linux-kernel - Re: [RFC PATCH 0/3] ACPI: platform_profile: Let drivers dynamically refresh choices

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Message-ID: <CALiyAonp1eow2ht_Cmux0B5+-Ukx7YxsE59c4VzwfSvL61iQ5g@mail.gmail.com>
Date: Tue, 7 Jan 2025 22:03:12 +0530
From: Hridesh MG <hridesh699@...il.com>
To: Mario Limonciello <mario.limonciello@....com>
Cc: Mark Pearson <mpearson-lenovo@...ebb.ca>, Kurt Borja <kuurtb@...il.com>, 
	"platform-driver-x86@...r.kernel.org" <platform-driver-x86@...r.kernel.org>, josh@...huagrisham.com, 
	"Derek J . Clark" <derekjohn.clark@...il.com>, "Rafael J. Wysocki" <rafael@...nel.org>, 
	Len Brown <lenb@...nel.org>, Maximilian Luz <luzmaximilian@...il.com>, 
	Hans de Goede <hdegoede@...hat.com>, Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>, 
	Lee Chun-Yi <jlee@...e.com>, Shyam Sundar S K <Shyam-sundar.S-k@....com>, 
	Corentin Chary <corentin.chary@...il.com>, "Luke D . Jones" <luke@...nes.dev>, 
	Lyndon Sanche <lsanche@...deno.ca>, Ike Panhc <ike.pan@...onical.com>, 
	Henrique de Moraes Holschuh <hmh@....eng.br>, Armin Wolf <W_Armin@....de>, Colin Ian King <colin.i.king@...il.com>, 
	Alexis Belmonte <alexbelm48@...il.com>, Uwe Kleine-König <u.kleine-koenig@...libre.com>, 
	Ai Chao <aichao@...inos.cn>, Gergo Koteles <soyer@....hu>, 
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>, linux-kernel@...r.kernel.org, 
	Dell.Client.Kernel@...l.com, ibm-acpi-devel@...ts.sourceforge.net
Subject: Re: [RFC PATCH 0/3] ACPI: platform_profile: Let drivers dynamically
 refresh choices

On Tue, Jan 7, 2025 at 9:21 PM Mario Limonciello
<mario.limonciello@....com> wrote:
>
> On 1/7/2025 07:14, Hridesh MG wrote:
> > On Tue, Jan 7, 2025 at 7:49 AM Mark Pearson <mpearson-lenovo@...ebb.ca> wrote:
> >>
> >> Hi Kurt,
> >>
> >> On Sun, Jan 5, 2025, at 11:45 PM, Kurt Borja wrote:
> >>> Hello,
> >>>
> >>> Some drivers may need to dynamically modify their selected `choices`.
> >>> Such is the case of the acer-wmi driver, which implemented their own
> >>> profile cycling method, because users expect different profiles to be
> >>> available whether the laptop is on AC or not [1].
> >>>
> >>> These series would allow acer-wmi to simplify this custom cycling method
> >>> to use platform_profile_cycle(), as it's already being proposed in these
> >>> series [2]; without changing expected behaviors, by refreshing their
> >>> selected choices on AC connect/disconnect events, which would also solve
> >>> this discussion [3].
> >>>
> >>> Additionally, I think the platform_profile_ops approach would enable us
> >>> to hide the platform_profile_handler in the future, and instead just pass
> >>> the class device to get/set methods like the HWMON subsystem does.
> >>>
> >>> I think having this kind of flexibility is valuable. Let me know what you
> >>> think!
> >>>
> >>
> >> I personally would love to see how this would be used for the acer issue highlighted to see how it would work out. It feels like the series is short a patch :)
> >
> > I do think that having this flexibility would be good, as i was
> > considering manually clearing the set bits and calling platform_notify
> > for the acer series, but in my specific case (for devices using the
> > predator v4 interface) it was found that the hardware was responsive
> > to all profiles regardless of AC/battery mode so it made sense to
> > leave this kind of artificial limiting of profiles to the
> > userspace--similar to how the Windows driver handles it through the
> > Nitro Sense app.
> >
> > I feel like users should have the power to utilize their hardware in
> > the way they want it to, though if there is a compelling reason to
> > limit the profiles then i'd be more than happy to add this to the
> > series :)
> >
> >
> > --
> > Hridesh MG
>
> I agree with Mark, this series is missing the patch that shows exactly
> how this would be used.  Furthermore; what exactly are the differences
> in choices between AC or DC?
On the predator series, the Windows OEM application only allows you to
select the low-power and balanced platform profiles on DC. These
profiles can however still be activated through WMI methods and the
hardware will apply them.

> To "userspace" I fail to understand how "balanced" is different from AC
> to DC for example.
It is not, the profiles or states themselves are not modified between
AC and DC, just the switching between them is affected.

-- 
Thanks,
Hridesh MG