Messages in this thread | | | From | "Rafael J. Wysocki" <> | Date | Fri, 14 Apr 2023 20:43:42 +0200 | Subject | Re: [PATCH v1 09/11] thermal/core: Add a linked device parameter |
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On Tue, Apr 4, 2023 at 9:01 PM Daniel Lezcano <daniel.lezcano@linaro.org> wrote: > > On 27/03/2023 18:16, Rafael J. Wysocki wrote: > > On Tue, Mar 7, 2023 at 2:38 PM Daniel Lezcano <daniel.lezcano@linaro.org> wrote: > >> > >> Some drivers want to create a link from the thermal zone to the device > >> sysfs entry and vice versa. > > > > Which device is this, exactly? > > ls -alh /sys/bus/acpi/drivers/thermal/LNXTHERM:00/ > > [ ... ] > > lrwxrwxrwx 1 0 thermal_zone -> > ../../../virtual/thermal/thermal_zone0 > > [ ... ] > > The ACPI driver is the only one doing this AFAICT. > > > >> That is the case of the APCI driver. > >> > >> Having a backpointer from the device to the thermal zone sounds akward > >> as we can have the same device instantiating multiple thermal zones so > >> there will be a conflict while creating the second link with the same > >> name. Moreover, the userspace has enough information to build the > >> dependency from the thermal zone device link without having this cyclic > >> link from the device to thermal zone. > >> > >> Anyway, everything in its time. > >> > >> This change allows to create a these cyclic links tz <-> device as > >> ACPI does and will allow to remove the code in the ACPI driver. > > > > Well, I'd rather have it in the driver than in the core TBH. > > > > If ACPI is the only user of this, let it do the dirty thing by itself. > > > > There are two cases which would justify making this change: > > 1. There will be more users of it going forward (seems unlikely from > > the description). > > 2. It gets in the way of some other changes somehow. > > > > I kind of expect 2. to be the case, so how does it get in the way? > > Shall we do the same approach than 'Menlow' and add an option to remove > the thermal zone link in the acpi sysfs directory ?
That depends on the answer to the question above.
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