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

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Message-ID: <CAJZ5v0gOqNi+-Hi8uyeEJ9dHzhwU6GyL6t_7Xjt5Knf2yJmH-w@mail.gmail.com>
Date: Mon, 26 Aug 2024 14:14:17 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Marek Szyprowski <m.szyprowski@...sung.com>
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 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.

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!