linux-kernel - Re: [PATCH v3 06/14] thermal: core: Introduce .should

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Message-ID: <916f784f-e6e2-c742-6948-5f2db688ba44@huawei.com>
Date: Wed, 21 Aug 2024 17:09:57 +0800
From: "lihuisong (C)" <lihuisong@...wei.com>
To: "Rafael J. Wysocki" <rjw@...ysocki.net>, Linux PM
	<linux-pm@...r.kernel.org>
CC: LKML <linux-kernel@...r.kernel.org>, Daniel Lezcano
	<daniel.lezcano@...aro.org>, Lukasz Luba <lukasz.luba@....com>, Zhang Rui
	<rui.zhang@...el.com>
Subject: Re: [PATCH v3 06/14] thermal: core: Introduce .should_bind() thermal
 zone callback


在 2024/8/20 0:00, Rafael J. Wysocki 写道:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>
> The current design of the code binding cooling devices to trip points in
> thermal zones is convoluted and hard to follow.
>
> Namely, a driver that registers a thermal zone can provide .bind()
> and .unbind() operations for it, which are required to call either
> thermal_bind_cdev_to_trip() and thermal_unbind_cdev_from_trip(),
> respectively, or thermal_zone_bind_cooling_device() and
> thermal_zone_unbind_cooling_device(), respectively, for every relevant
> trip point and the given cooling device.  Moreover, if .bind() is
> provided and .unbind() is not, the cleanup necessary during the removal
> of a thermal zone or a cooling device may not be carried out.
>
> In other words, the core relies on the thermal zone owners to do the
> right thing, which is error prone and far from obvious, even though all
> of that is not really necessary.  Specifically, if the core could ask
> the thermal zone owner, through a special thermal zone callback, whether
> or not a given cooling device should be bound to a given trip point in
> the given thermal zone, it might as well carry out all of the binding
> and unbinding by itself.  In particular, the unbinding can be done
> automatically without involving the thermal zone owner at all because
> all of the thermal instances associated with a thermal zone or cooling
> device going away must be deleted regardless.
>
> Accordingly, introduce a new thermal zone operation, .should_bind(),
> that can be invoked by the thermal core for a given thermal zone,
> trip point and cooling device combination in order to check whether
> or not the cooling device should be bound to the trip point at hand.
> It takes an additional cooling_spec argument allowing the thermal
> zone owner to specify the highest and lowest cooling states of the
> cooling device and its weight for the given trip point binding.
>
> Make the thermal core use this operation, if present, in the absence of
> .bind() and .unbind().  Note that .should_bind() will be called under
> the thermal zone lock.
>
> No intentional functional impact.
>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> ---
all thermal zone is linked to thermal_tz_list and cooling devices is 
linked to thermal_cdev_list.
But if one cooling device should bind to a trip in thermal zone is 
determined by thermal driver.
Introducing should_bind() looks good to me.
Acked-by: Huisong Li <lihuisong@...wei.com>
>
>
>
>
> .