在 2024/11/14 19:53, Rafael J. Wysocki 写道:
Hi,
On Thu, Nov 14, 2024 at 9:37 AM lihuisong (C) <lihuisong@xxxxxxxxxx> wrote:
Hi Rafael,
在 2024/11/13 17:26, Rafael J. Wysocki 写道:
On Wed, Nov 13, 2024 at 10:07 AM Huisong Li <lihuisong@xxxxxxxxxx> wrote:
There are many 'cdevX' files which link cooling devices under
'/sys/class/thermal/thermal_zoneX/'. These devices contain active cooling
devices and passive cooling devices. And user cann't directly know which
devices temperature is represented by the thermal zone.
However, ACPI spec provides a '_TZD' object which evaluates to a package
of device names. Each name corresponds to a device in the ACPI namespace
that is associated with the thermal zone. The temperature reported by the
thermal zone is roughly correspondent to that of each of the devices.
User can get all devices a thermal zone measured by the 'measures'
directory under the thermal zone device.
Well, that's kind of clear, but what exactly is the use case? Why
does the user need to know that?
IMO, this makes thermal zone information more friendly.
For instance, user can directly know the temperature of CPUs or other
devices is roughly represented by which thermal zone.
This may offer the convenience for further usersapce application.
BTW, the '_TZD' method is similar to the '_PMD' in acpi power meter.
Since ACPI spec provides them, they should also have a role in their
existence.
So there is no specific use case, but it is possible that somebody may
want to use this information, IIUC.
Well, let's defer making kernel changes until there is a user
wanting/needing this information. Then we'll decide how to expose it.
For one, I'm not convinced that exposing it under the ACPI
representation of a thermal zone is going to be really useful.
All right. Thanks for your review.
.
