Message-ID: <d8533a76-9626-dcc2-f3fb-de878d2603df@linaro.org>
Date:   Mon, 3 Oct 2022 17:36:34 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Marek Szyprowski <m.szyprowski@...sung.com>, rafael@...nel.org
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        rui.zhang@...el.com,
        Broadcom Kernel Team <bcm-kernel-feedback-list@...adcom.com>,
        Support Opensource <support.opensource@...semi.com>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        NXP Linux Team <linux-imx@....com>,
        Andy Gross <agross@...nel.org>,
        Bartlomiej Zolnierkiewicz <bzolnier@...il.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Alim Akhtar <alim.akhtar@...sung.com>, netdev@...r.kernel.org,
        platform-driver-x86@...r.kernel.org,
        linux-rpi-kernel@...ts.infradead.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, linux-renesas-soc@...r.kernel.org,
        linux-samsung-soc@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-omap@...r.kernel.org
Subject: Re: [PATCH v8 00/29] Rework the trip points creation

On 03/10/2022 16:10, Marek Szyprowski wrote:
> Hi Daniel,
> 
> On 03.10.2022 11:25, Daniel Lezcano wrote:
>> This work is the pre-requisite of handling correctly when the trip
>> point are crossed. For that we need to rework how the trip points are
>> declared and assigned to a thermal zone.
>>
>> Even if it appears to be a common sense to have the trip points being
>> ordered, this no guarantee neither documentation telling that is the
>> case.
>>
>> One solution could have been to create an ordered array of trips built
>> when registering the thermal zone by calling the different get_trip*
>> ops. However those ops receive a thermal zone pointer which is not
>> known as it is in the process of creating it.
>>
>> This cyclic dependency shows we have to rework how we manage the trip
>> points.
>>
>> Actually, all the trip points definition can be common to the backend
>> sensor drivers and we can factor out the thermal trip structure in all
>> of them.
>>
>> Then, as we register the thermal trips array, they will be available
>> in the thermal zone structure and a core function can return the trip
>> given its id.
>>
>> The get_trip_* ops won't be needed anymore and could be removed. The
>> resulting code will be another step forward to a self encapsulated
>> generic thermal framework.
>>
>> Most of the drivers can be converted more or less easily. This series
>> does a first round with most of the drivers. Some remain and will be
>> converted but with a smaller set of changes as the conversion is a bit
>> more complex.
>>
>> Changelog:
>> v8:
>> - Pretty oneline change and parenthesis removal (Rafael)
>> - Collected tags
>> v7:
>> - Added missing return 0 in the x86_pkg_temp driver
>> v6:
>> - Improved the code for the get_crit_temp() function as suggested by
>> Rafael
>> - Removed inner parenthesis in the set_trip_temp() function and invert the
>> conditions. Check the type of the trip point is unchanged
>> - Folded patch 4 with 1
>> - Add per thermal zone info message in the bang-bang governor
>> - Folded the fix for an uninitialized variable in
>> int340x_thermal_zone_add()
>> v5:
>> - Fixed a deadlock when calling thermal_zone_get_trip() while
>> handling the thermal zone lock
>> - Remove an extra line in the sysfs change
>> - Collected tags
>> v4:
>> - Remove extra lines on exynos changes as reported by Krzysztof Kozlowski
>> - Collected tags
>> v3:
>> - Reorg the series to be git-bisect safe
>> - Added the set_trip generic function
>> - Added the get_crit_temp generic function
>> - Removed more dead code in the thermal-of
>> - Fixed the exynos changelog
>> - Fixed the error check for the exynos drivers
>> - Collected tags
>> v2:
>> - Added missing EXPORT_SYMBOL_GPL() for thermal_zone_get_trip()
>> - Removed tab whitespace in the acerhdf driver
>> - Collected tags
>>
>> Cc: Raju Rangoju <rajur@...lsio.com>
>> Cc: "David S. Miller" <davem@...emloft.net>
>> Cc: Eric Dumazet <edumazet@...gle.com>
>> Cc: Jakub Kicinski <kuba@...nel.org>
>> Cc: Paolo Abeni <pabeni@...hat.com>
>> Cc: Peter Kaestle <peter@...e.net>
>> Cc: Hans de Goede <hdegoede@...hat.com>
>> Cc: Mark Gross <markgross@...nel.org>
>> Cc: Miquel Raynal <miquel.raynal@...tlin.com>
>> Cc: "Rafael J. Wysocki" <rafael@...nel.org>
>> Cc: Daniel Lezcano <daniel.lezcano@...aro.org>
>> Cc: Amit Kucheria <amitk@...nel.org>
>> Cc: Zhang Rui <rui.zhang@...el.com>
>> Cc: Nicolas Saenz Julienne <nsaenz@...nel.org>
>> Cc: Broadcom Kernel Team <bcm-kernel-feedback-list@...adcom.com>
>> Cc: Florian Fainelli <f.fainelli@...il.com>
>> Cc: Ray Jui <rjui@...adcom.com>
>> Cc: Scott Branden <sbranden@...adcom.com>
>> Cc: Support Opensource <support.opensource@...semi.com>
>> Cc: Lukasz Luba <lukasz.luba@....com>
>> Cc: Shawn Guo <shawnguo@...nel.org>
>> Cc: Sascha Hauer <s.hauer@...gutronix.de>
>> Cc: Pengutronix Kernel Team <kernel@...gutronix.de>
>> Cc: Fabio Estevam <festevam@...il.com>
>> Cc: NXP Linux Team <linux-imx@....com>
>> Cc: Thara Gopinath <thara.gopinath@...aro.org>
>> Cc: Andy Gross <agross@...nel.org>
>> Cc: Bjorn Andersson <bjorn.andersson@...aro.org>
>> Cc: "Niklas Söderlund" <niklas.soderlund@...natech.se>
>> Cc: Bartlomiej Zolnierkiewicz <bzolnier@...il.com>
>> Cc: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
>> Cc: Alim Akhtar <alim.akhtar@...sung.com>
>> Cc: Thierry Reding <thierry.reding@...il.com>
>> Cc: Jonathan Hunter <jonathanh@...dia.com>
>> Cc: Eduardo Valentin <edubezval@...il.com>
>> Cc: Keerthy <j-keerthy@...com>
>> Cc: Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>
>> Cc: Masami Hiramatsu <mhiramat@...nel.org>
>> Cc: Antoine Tenart <atenart@...nel.org>
>> Cc: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
>> Cc: Dmitry Osipenko <digetx@...il.com>
>> Cc: netdev@...r.kernel.org
>> Cc: linux-kernel@...r.kernel.org
>> Cc: platform-driver-x86@...r.kernel.org
>> Cc: linux-pm@...r.kernel.org
>> Cc: linux-rpi-kernel@...ts.infradead.org
>> Cc: linux-arm-kernel@...ts.infradead.org
>> Cc: linux-arm-msm@...r.kernel.org
>> Cc: linux-renesas-soc@...r.kernel.org
>> Cc: linux-samsung-soc@...r.kernel.org
>> Cc: linux-tegra@...r.kernel.org
>> Cc: linux-omap@...r.kernel.org
>>
>> Daniel Lezcano (29):
>> thermal/core: Add a generic thermal_zone_get_trip() function
>> thermal/sysfs: Always expose hysteresis attributes
>> thermal/core: Add a generic thermal_zone_set_trip() function
>> thermal/core/governors: Use thermal_zone_get_trip() instead of ops
>> functions
>> thermal/of: Use generic thermal_zone_get_trip() function
>> thermal/of: Remove unused functions
>> thermal/drivers/exynos: Use generic thermal_zone_get_trip() function
>> thermal/drivers/exynos: of_thermal_get_ntrips()
>> thermal/drivers/exynos: Replace of_thermal_is_trip_valid() by
>> thermal_zone_get_trip()
>> thermal/drivers/tegra: Use generic thermal_zone_get_trip() function
>> thermal/drivers/uniphier: Use generic thermal_zone_get_trip() function
>> thermal/drivers/hisi: Use generic thermal_zone_get_trip() function
>> thermal/drivers/qcom: Use generic thermal_zone_get_trip() function
>> thermal/drivers/armada: Use generic thermal_zone_get_trip() function
>> thermal/drivers/rcar_gen3: Use the generic function to get the number
>> of trips
>> thermal/of: Remove of_thermal_get_ntrips()
>> thermal/of: Remove of_thermal_is_trip_valid()
>> thermal/of: Remove of_thermal_set_trip_hyst()
>> thermal/of: Remove of_thermal_get_crit_temp()
>> thermal/drivers/st: Use generic trip points
>> thermal/drivers/imx: Use generic thermal_zone_get_trip() function
>> thermal/drivers/rcar: Use generic thermal_zone_get_trip() function
>> thermal/drivers/broadcom: Use generic thermal_zone_get_trip() function
>> thermal/drivers/da9062: Use generic thermal_zone_get_trip() function
>> thermal/drivers/ti: Remove unused macros ti_thermal_get_trip_value() /
>> ti_thermal_trip_is_valid()
>> thermal/drivers/acerhdf: Use generic thermal_zone_get_trip() function
>> thermal/drivers/cxgb4: Use generic thermal_zone_get_trip() function
>> thermal/intel/int340x: Replace parameter to simplify
>> thermal/drivers/intel: Use generic thermal_zone_get_trip() function
> 
> I've tested this v8 patchset after fixing the issue with Exynos TMU with
> https://lore.kernel.org/all/20221003132943.1383065-1-daniel.lezcano@linaro.org/
> patch and I got the following lockdep warning on all Exynos-based boards:
>
> ======================================================
> WARNING: possible circular locking dependency detected
> 6.0.0-rc1-00083-ge5c9d117223e #12945 Not tainted
> ------------------------------------------------------
> swapper/0/1 is trying to acquire lock:
> c1ce66b0 (&data->lock#2){+.+.}-{3:3}, at: exynos_get_temp+0x3c/0xc8
> 
> but task is already holding lock:
> c2979b94 (&tz->lock){+.+.}-{3:3}, at:
> thermal_zone_device_update.part.0+0x3c/0x528
> 
> which lock already depends on the new lock.

Investigating ...



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