linux-kernel - Re: [PATCH v4 13/20] ACPI: platform_profile: Notify change events on register and unregister

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Message-ID: <8ac7f4b6-525f-4394-a4e7-36640359ea17@gmx.de>
Date: Wed, 6 Nov 2024 21:58:22 +0100
From: Armin Wolf <W_Armin@....de>
To: Mario Limonciello <mario.limonciello@....com>,
 Hans de Goede <hdegoede@...hat.com>,
 Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc: "Rafael J . Wysocki" <rafael@...nel.org>, Len Brown <lenb@...nel.org>,
 Maximilian Luz <luzmaximilian@...il.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>, Ike Panhc <ike.pan@...onical.com>,
 Henrique de Moraes Holschuh <hmh@....eng.br>,
 Alexis Belmonte <alexbelm48@...il.com>,
 Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
 Ai Chao <aichao@...inos.cn>, Gergo Koteles <soyer@....hu>,
 open list <linux-kernel@...r.kernel.org>,
 "open list:ACPI" <linux-acpi@...r.kernel.org>,
 "open list:MICROSOFT SURFACE PLATFORM PROFILE DRIVER"
 <platform-driver-x86@...r.kernel.org>,
 "open list:THINKPAD ACPI EXTRAS DRIVER"
 <ibm-acpi-devel@...ts.sourceforge.net>,
 Mark Pearson <mpearson-lenovo@...ebb.ca>,
 Matthew Schwartz <matthew.schwartz@...ux.dev>
Subject: Re: [PATCH v4 13/20] ACPI: platform_profile: Notify change events on
 register and unregister

Am 06.11.24 um 20:44 schrieb Mario Limonciello:

> On 11/6/2024 13:40, Armin Wolf wrote:
>> Am 05.11.24 um 16:33 schrieb Mario Limonciello:
>>
>>> As multiple platform profile handlers may come and go, send a
>>> notification
>>> to userspace each time that a platform profile handler is registered or
>>> unregistered.
>>>
>>> Tested-by: Matthew Schwartz <matthew.schwartz@...ux.dev>
>>> Reviewed-by: Mark Pearson <mpearson-lenovo@...ebb.ca>
>>> Signed-off-by: Mario Limonciello <mario.limonciello@....com>
>>> ---
>>>   drivers/acpi/platform_profile.c | 5 ++++-
>>>   1 file changed, 4 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/acpi/platform_profile.c b/drivers/acpi/
>>> platform_profile.c
>>> index 79083d0bb22e3..c9917daf683cb 100644
>>> --- a/drivers/acpi/platform_profile.c
>>> +++ b/drivers/acpi/platform_profile.c
>>> @@ -404,6 +404,7 @@ int platform_profile_register(struct
>>> platform_profile_handler *pprof)
>>>       if (IS_ERR(pprof->class_dev))
>>>           return PTR_ERR(pprof->class_dev);
>>>       dev_set_drvdata(pprof->class_dev, pprof);
>>> +    sysfs_notify(acpi_kobj, NULL, "platform_profile");
>>>
>>>       cur_profile = pprof;
>>>       return 0;
>>> @@ -419,7 +420,9 @@ int platform_profile_remove(struct
>>> platform_profile_handler *pprof)
>>>   {
>>>       guard(mutex)(&profile_lock);
>>>
>>> -    sysfs_remove_group(acpi_kobj, &platform_profile_group);
>>
>> When do we remove platform_profile_group now?
>>
>
> When incorporating your other feedback I noticed this was still there
> and it will be removed for the next revision.
>
> The idea will be as soon as a class registers the legacy interface is
> created and will stay for the lifetime of the boot.
>
> If all drivers are unloaded it will return -EINVAL until a new driver
> is loaded.

And what happens when the platform profile core itself is unloaded?

Thanks,
Armin Wolf

>
>> Thanks,
>> Armin Wolf
>>
>>> +    cur_profile = NULL;
>>> +
>>> +    sysfs_notify(acpi_kobj, NULL, "platform_profile");
>>>
>>>       device_destroy(&platform_profile_class, MKDEV(0, pprof->minor));
>>>
>
>