From: "Rafael J. Wysocki" <rafael@kernel.org>
To: Wolfram Sang <wsa@kernel.org>
Cc: Linux PM <linux-pm@vger.kernel.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-i2c <linux-i2c@vger.kernel.org>
Subject: Re: RFC: a failing pm_runtime_get increases the refcnt?
Date: Sun, 14 Jun 2020 15:50:11 +0200 [thread overview]
Message-ID: <CAJZ5v0g0qJDrEvRrxEboc1Bs_9dgqpV47rFOZrJQLvOS44nAXg@mail.gmail.com> (raw)
In-Reply-To: <20200614090751.GA2878@kunai>
On Sun, Jun 14, 2020 at 11:08 AM Wolfram Sang <wsa@kernel.org> 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
pm_runtime_get*()
...
pm_runtime_put*()
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
clear.
Cheers!
prev parent reply other threads:[~2020-06-14 13:50 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-14 9:07 RFC: a failing pm_runtime_get increases the refcnt? Wolfram Sang
2020-06-14 9:34 ` Andy Shevchenko
2020-06-14 9:42 ` Andy Shevchenko
2020-06-14 10:00 ` Geert Uytterhoeven
2020-06-14 10:04 ` Geert Uytterhoeven
2020-06-14 10:44 ` Andy Shevchenko
2020-06-14 12:42 ` Andy Shevchenko
2020-06-14 13:59 ` Rafael J. Wysocki
2020-06-14 14:07 ` Wolfram Sang
2020-06-30 19:48 ` Wolfram Sang
2020-06-14 13:50 ` Rafael J. Wysocki [this message]
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