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From: "Rafael J. Wysocki" <rafael@kernel.org>
To: David Wang <00107082@163.com>
Cc: len.brown@intel.com, pavel@ucw.cz, gregkh@linuxfoundation.org,
	 linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] PM: add: move warn message out of mutex lock.
Date: Tue, 3 Sep 2024 16:10:16 +0200	[thread overview]
Message-ID: <CAJZ5v0itLuorOY-4PyDL5eFkWTf2s9JX++oBkzqi1cYcaHYdmA@mail.gmail.com> (raw)
In-Reply-To: <CAJZ5v0gZ9oAByawssaARFN1_crTuMZ-CnU5Fy9D1sWv+Moo-sg@mail.gmail.com>

On Tue, Sep 3, 2024 at 3:01 PM Rafael J. Wysocki <rafael@kernel.org> wrote:
>
> On Mon, Sep 2, 2024 at 7:50 AM David Wang <00107082@163.com> wrote:
> >
> > dpm_list_mtx does not protect any data used by
> > dev_warn for checking parent's power, move
> > dev_warn out of mutex lock block make the
> > lock more efficient, especially when the warn
> > is triggered.
>
> It does protect the power.is_prepared flag of the parent.

In fact, the update of it in device_resume() is racy with respect to
the check in device_pm_add(), but the purpose of it is mostly to allow
the device driver's resume callback to add children without triggering
the warning.

  reply	other threads:[~2024-09-03 14:10 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-09-02  5:49 David Wang
2024-09-02  6:31 ` Greg KH
2024-09-02  6:47   ` David Wang
2024-09-03 13:01 ` Rafael J. Wysocki
2024-09-03 14:10   ` Rafael J. Wysocki [this message]
2024-09-03 16:16     ` David Wang
2024-09-03 16:23       ` Rafael J. Wysocki
2024-09-03 16:42         ` David Wang

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