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Date:   Sun, 14 Jun 2020 15:50:11 +0200
From:   "Rafael J. Wysocki" <>
To:     Wolfram Sang <>
Cc:     Linux PM <>,
        "Rafael J. Wysocki" <>,
        Linux-Renesas <>,
        Linux Kernel Mailing List <>,
        linux-i2c <>
Subject: Re: RFC: a failing pm_runtime_get increases the refcnt?

On Sun, Jun 14, 2020 at 11:08 AM Wolfram Sang <> wrote:
> Hi Linux-PM,
> both in the I2C subsystem and also for Renesas drivers I maintain, I am
> starting to get boilerplate patches doing some pm_runtime_put_* variant
> because a failing pm_runtime_get is supposed to increase the ref
> counters? Really?

Yes.  Really.

pm_runtime_get*() have been doing this forever, because the majority
of their users do something like




without checking the return values and they don't need to worry about
the refcounts, which wouldn't be possible otherwise.

> This feels wrong and unintuitive to me. I expect there
> has been a discussion around it but I couldn't find it. I wonder why we
> don't fix the code where the incremented refcount is expected for some
> reason.
> Can I have some pointers please?

The behavior is actually documented in
Documentation/power/runtime_pm.rst and I'm working on kerneldoc
comments for runtime PM functions in general to make it a bit more


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