linux-kernel - Re: [PATCH v3 12/14] thermal/of: Use the .should

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Message-ID: <0e710ff1-4ff4-403a-b85d-b1e51c03378a@samsung.com>
Date: Mon, 26 Aug 2024 22:49:45 +0200
From: Marek Szyprowski <m.szyprowski@...sung.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>, Linux PM
	<linux-pm@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>, Daniel
	Lezcano <daniel.lezcano@...aro.org>, Lukasz Luba <lukasz.luba@....com>,
	Zhang Rui <rui.zhang@...el.com>, Krzysztof Kozlowski
	<krzysztof.kozlowski@...aro.org>, Linux Samsung SOC
	<linux-samsung-soc@...r.kernel.org>, Mateusz Majewski
	<m.majewski2@...sung.com>, linux-amlogic@...ts.infradead.org
Subject: Re: [PATCH v3 12/14] thermal/of: Use the .should_bind() thermal
 zone callback

On 26.08.2024 14:14, Rafael J. Wysocki wrote:
> On Mon, Aug 26, 2024 at 1:32 PM Marek Szyprowski
> <m.szyprowski@...sung.com> wrote:
>> On 19.08.2024 18:30, Rafael J. Wysocki wrote:
>>> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>>>
>>> Make the thermal_of driver use the .should_bind() thermal zone callback
>>> to provide the thermal core with the information on whether or not to
>>> bind the given cooling device to the given trip point in the given
>>> thermal zone.  If it returns 'true', the thermal core will bind the
>>> cooling device to the trip and the corresponding unbinding will be
>>> taken care of automatically by the core on the removal of the involved
>>> thermal zone or cooling device.
>>>
>>> This replaces the .bind() and .unbind() thermal zone callbacks which
>>> assumed the same trip points ordering in the driver and in the thermal
>>> core (that may not be true any more in the future).  The .bind()
>>> callback would walk the given thermal zone's cooling maps to find all
>>> of the valid trip point combinations with the given cooling device and
>>> it would call thermal_zone_bind_cooling_device() for all of them using
>>> trip point indices reflecting the ordering of the trips in the DT.
>>>
>>> The .should_bind() callback still walks the thermal zone's cooling maps,
>>> but it can use the trip object passed to it by the thermal core to find
>>> the trip in question in the first place and then it uses the
>>> corresponding 'cooling-device' entries to look up the given cooling
>>> device.  To be able to match the trip object provided by the thermal
>>> core to a specific device node, the driver sets the 'priv' field of each
>>> trip to the corresponding device node pointer during initialization.
>>>
>>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>> This patch landed recently in linux-next as commit 6d71d55c3b12
>> ("thermal/of: Use the .should_bind() thermal zone callback")
> It has been fixed since and it is commit  94c6110b0b13c6416146 now.


Confirmed. Thanks for fixing it and sorry for the noise.


> Bottom line is that it was calling of_node_put() too many times due to
> a coding mistake.
>
>> In my tests I found that it breaks booting some on my test boars: Exynos-based
>> (OdroidXU4 with ARM32 bit kernel from multi_v7_defconfig) and Amlogic
>> Meson based boards (OdroidC4, VIM3 with ARM64 defconfig+some debug
>> options). Reverting $subject on top of next-20240823 together with
>> c1ee6e1f68f5 ("thermal: core: Clean up trip bind/unbind functions") and
>> 526954900465 ("thermal: core: Drop unused bind/unbind functions and
>> callbacks") due to compile dependencies fixes the issue.
> Thanks for the report!
>
Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland