linux-kernel - [RFD] Remove the userspace governor and the cooling device set state sysfs entry

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Message-ID: <d46b5007-428b-5f31-52d9-a964cc60ad92@linaro.org>
Date:   Wed, 22 Sep 2021 11:59:32 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Zhang Rui <rui.zhang@...el.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Linux PM mailing list <linux-pm@...r.kernel.org>
Subject: [RFD] Remove the userspace governor and the cooling device set state
 sysfs entry

Hi,

the userspace governor is sending temperature when polling is active and
trip point crossed events. Nothing else.

In the other side, the cooling device have their cooling device
set_cur_state read-writable all the time.

The thermal framework is wrongly used by userspace as a power capping
framework by acting on the cooling device opaque state. This one then
competes with the in-kernel governor decision.

As the new netlink thermal notification is able to provide the same
information than the userspace governor.

I propose to remove the userspace governor and the cur_state entry in
the sysfs exported file.

The DTPM framework is the right framework to do power capping and
moreover it deals with the aggregation via the dev pm qos.

Does it make sense ?

  -- Daniel

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