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Date: Thu, 22 Feb 2024 14:50:11 +0100
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Subject: Re: [PATCH v2 1/9] thermal: Get rid of CONFIG_THERMAL_WRITABLE_TRIPS
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To: "Rafael J. Wysocki" <rjw@rjwysocki.net>,
 Linux PM <linux-pm@vger.kernel.org>
Cc: Lukasz Luba <lukasz.luba@arm.com>, LKML <linux-kernel@vger.kernel.org>,
 Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>,
 Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
 Zhang Rui <rui.zhang@intel.com>, netdev@vger.kernel.org,
 Ido Schimmel <idosch@nvidia.com>, Petr Machata <petrm@nvidia.com>,
 Miri Korenblit <miriam.rachel.korenblit@intel.com>,
 linux-wireless@vger.kernel.org, Shawn Guo <shawnguo@kernel.org>,
 Sascha Hauer <s.hauer@pengutronix.de>,
 Pengutronix Kernel Team <kernel@pengutronix.de>,
 Manaf Meethalavalappu Pallikunhi <quic_manafm@quicinc.com>
References: <6017196.lOV4Wx5bFT@kreacher> <4545870.LvFx2qVVIh@kreacher>
From: Daniel Lezcano <daniel.lezcano@linaro.org>
In-Reply-To: <4545870.LvFx2qVVIh@kreacher>
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On 12/02/2024 19:26, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> 
> The only difference made by CONFIG_THERMAL_WRITABLE_TRIPS is whether or
> not the writable trips mask passed during thermal zone registration
> will take any effect, but whoever passes a non-zero writable trips mask
> to thermal_zone_device_register_with_trips() can be forgiven thinking
> that it will always work.
> 
> Moreover, some thermal drivers expect user space to set trip temperature
> values, so they select CONFIG_THERMAL_WRITABLE_TRIPS, possibly overriding
> a manual choice to unset it and going against the design purportedly
> allowing system integrators to decide on the writability of trip points
> for the given kernel build.  It is also set in one platform's defconfig.
> 
> Forthermore, CONFIG_THERMAL_WRITABLE_TRIPS only affects trip temperature,
> because trip hysteresis is writable as long as the thermal zone provides
> a callback to update it, regardless of the CONFIG_THERMAL_WRITABLE_TRIPS
> value.
> 
> The above means that the symbol in question is used inconsistently and
> its purpose is at least moot, so remove it and always take the writable
> trip mask passed to thermal_zone_device_register_with_trips() into
> account.
> 
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>


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