linux-kernel - Re: [PATCH v5 0/3] Thermal ACPI APIs for generic trip points

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Message-ID: <87627e1f-322c-a195-8ce6-8922d9787ff0@linaro.org>
Date:   Wed, 18 Jan 2023 22:01:23 +0100
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     srinivas pandruvada <srinivas.pandruvada@...ux.intel.com>,
        "Zhang, Rui" <rui.zhang@...el.com>,
        "rafael@...nel.org" <rafael@...nel.org>
Cc:     "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "christophe.jaillet@...adoo.fr" <christophe.jaillet@...adoo.fr>,
        "linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>
Subject: Re: [PATCH v5 0/3] Thermal ACPI APIs for generic trip points

On 18/01/2023 21:53, srinivas pandruvada wrote:
> On Wed, 2023-01-18 at 21:00 +0100, Daniel Lezcano wrote:
>> On 18/01/2023 20:16, srinivas pandruvada wrote:
>>
>> [ ... ]
>>
>>>>> But we'd better wait for the thermald test result from
>>>>> Srinvias.
>>>>
>>>> A quick test show that things still work with thermald and these
>>>> changes.
>>>
>>> But I have a question. In some devices trip point temperature is
>>> not
>>> static. When hardware changes, we get notification. For example
>>> INT3403_PERF_TRIP_POINT_CHANGED for INT3403 drivers.
>>> Currently get_trip can get the latest changed value. But if we
>>> preregister, we need some mechanism to update them.
>>
>> When the notification INT3403_PERF_TRIP_POINT_CHANGED happens, we
>> call
>> int340x_thermal_read_trips() which in turn updates the trip points.
>>
> 
> Not sure how we handle concurrency here when driver can freely update
> trips while thermal core is using trips.

Don't we have the same race without this patch ? The thermal core can 
call get_trip_temp() while there is an update, no ?

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