linux-kernel - Re: [PATCH v4 1/3] ACPI: platform-profile: add platform_profile

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Date: Fri, 05 Apr 2024 16:48:48 +0200
From: Gergo Koteles <soyer@....hu>
To: Daniel Lezcano <daniel.lezcano@...aro.org>,
  "Rafael J. Wysocki" <rafael@...nel.org>, Len Brown <lenb@...nel.org>,
  Ike Panhc <ike.pan@...onical.com>,
  Hans de Goede <hdegoede@...hat.com>,
  Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>,
  Henrique de Moraes Holschuh <hmh@....eng.br>
Cc: linux-acpi@...r.kernel.org, ibm-acpi-devel@...ts.sourceforge.net,
  platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 1/3] ACPI: platform-profile: add
 platform_profile_cycle()

Hi Daniel,

On Fri, 2024-04-05 at 08:48 +0200, Daniel Lezcano wrote:
> Hi Gergo,
> 
> please Cc people who commented your changes.

Thanks for this info, next time :)

> > +int platform_profile_cycle(void)
> > +{
> > +	enum platform_profile_option profile;
> > +	enum platform_profile_option next;
> > +	int err;
> > +
> > +	err = mutex_lock_interruptible(&profile_lock);
> > +	if (err)
> > +		return err;
> > +
> > +	if (!cur_profile) {
> > +		mutex_unlock(&profile_lock);
> > +		return -ENODEV;
> > +	}
> > +
> > +	err = cur_profile->profile_get(cur_profile, &profile);
> > +	if (err) {
> > +		mutex_unlock(&profile_lock);
> > +		return err;
> > +	}
> > +
> > +	next = ffs(cur_profile->choices[0] >> (profile + 1)) + profile;
> > +
> > +	/* current profile is the highest, select the lowest */
> > +	if (next == profile)
> > +		next = ffs(cur_profile->choices[0]) - 1;
> > +
> > +	if (WARN_ON((next < 0) || (next >= ARRAY_SIZE(profile_names)))) {
> > +		mutex_unlock(&profile_lock);
> > +		return -EINVAL;
> > +	}
> 
> Why do you need to do this?
> 

Many platform drivers use the platform profile module. They support
different sets of profiles, not all. They sets the corresponding bits
in the choices variable.

like this:
set_bit(PLATFORM_PROFILE_BALANCED, platform_profile_handler.choices);

The platform_profile_cycle() cycles through the enabled profiles.

Best regards,
Gergo

> That can be simplified by:
> 
> 	[ ... ]
> 
> 	err = cur_profile->profile_get(cur_profile, &profile);
> 	if (err)
> 		goto out;
> 
> 	profile = (profile + 1) % ARRAY_SIZE(profile_names);
> 
> 	err = cur_profile->profile_set(cur_profile, next);
> out:
> 	mutex_unlock(&profile_lock);
> 	
> 	[ ... ]
> 
> > +	err = cur_profile->profile_set(cur_profile, next);
> > +	mutex_unlock(&profile_lock);
> > +
> > +	if (!err)
> > +		sysfs_notify(acpi_kobj, NULL, "platform_profile");
> > +
> > +	return err;
> > +}
> > +EXPORT_SYMBOL_GPL(platform_profile_cycle);
> > +
> >   int platform_profile_register(struct platform_profile_handler *pprof)
> >   {
> >   	int err;
> > diff --git a/include/linux/platform_profile.h b/include/linux/platform_profile.h
> > index e5cbb6841f3a..f5492ed413f3 100644
> > --- a/include/linux/platform_profile.h
> > +++ b/include/linux/platform_profile.h
> > @@ -36,6 +36,7 @@ struct platform_profile_handler {
> >   
> >   int platform_profile_register(struct platform_profile_handler *pprof);
> >   int platform_profile_remove(void);
> > +int platform_profile_cycle(void);
> >   void platform_profile_notify(void);
> >   
> >   #endif  /*_PLATFORM_PROFILE_H_*/
>