From: "Bartłomiej Zimoń" <uzi18@o2.pl>
To: linux-kernel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, awalls@radix.net,
danborkmann@googlemail.com, linux-pm@lists.linux-foundation.org,
stern@rowland.harvard.edu, rjw@sisk.pl
Subject: Re: [suspend/resume] Re: userspace notification from module
Date: Mon, 04 Jan 2010 00:35:31 +0100 [thread overview]
Message-ID: <54ac764e.502c1a33.4b4129c3.9dc1b@o2.pl> (raw)
In-Reply-To: <201001040030.01256.rjw@sisk.pl>
Dnia 4 stycznia 2010 0:30 "Rafael J. Wysocki" <rjw@sisk.pl> napisał(a):
> On Sunday 03 January 2010, Bartłomiej Zimoń wrote:
> > Dnia 3 stycznia 2010 22:29 "Rafael J. Wysocki" <rjw@sisk.pl> napisał(a):
> ...
> >
> > It could be even UIO module but there are no pm events reachable there?
> >
> > If it is not clean, we must extend pm-utils or write something new
> > (with backends dbus, ipc, scripts, ...)
> > But You see? We still have no information from kernel about events
> > (especialy resume) or maybe i dont see this ;/
>
> They are available to the process that tells the kernel to suspend.
>
> Namely, to tell the kernel to suspend to RAM, the process (call it a power
> manager) needs to (for example) fprintf() "mem" to /sys/power/state. As soon
> as this happens, the kernel will start to freeze processes (except for the
> power manager itself), so the power manager knows that everything should be
> ready for the suspend before it writes to /sys/power/state. It doesn't need
> the kernel to tell it when the suspend is going to start, because it _knows_
> that in advance.
>
> Now, the fprintf() used to trigger the suspend will not return until the resume
> is complete. So, again, when the fprintf() returns, the power manager will know
> that the resume has just finished (more precisely, the kernel side of it has
> just finished).
>
> There simply is no need for any special communication between the kernel and
> the power manager.
>
Thx Rafael - now it clear to me.
And what do You think about sending extra signals to processes?
Best regards.
Bartłomiej Zimoń
PLD Linux, Kadu Team, FreeRunner user
http://kadu-im.blogspot.com/
next prev parent reply other threads:[~2010-01-03 23:35 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-02 13:29 userspace notification from module Bartłomiej Zimoń
2010-01-02 14:04 ` Daniel Borkmann
2010-01-02 14:27 ` [suspend/resume] " Bartłomiej Zimoń
2010-01-02 15:11 ` Oliver Neukum
[not found] ` <6f52f5b81001020713j5435cfadr1143806a9026adc2@mail.gmail.com>
2010-01-02 15:15 ` Daniel Borkmann
2010-01-02 15:40 ` Andy Walls
2010-01-02 15:56 ` Daniel Borkmann
2010-01-02 18:26 ` Bartłomiej Zimoń
2010-01-02 21:01 ` Rafael J. Wysocki
[not found] ` <7cf4f51f.5fc2a5cd.4b3fc3ad.c849c@o2.pl>
2010-01-02 23:29 ` Rafael J. Wysocki
2010-01-03 17:20 ` Bartłomiej Zimoń
2010-01-03 21:50 ` Rafael J. Wysocki
[not found] ` <65e5aef6.33251eb4.4b3fecf4.a2f99@o2.pl>
2010-01-03 9:30 ` Daniel Borkmann
2010-01-03 10:06 ` Daniel Borkmann
[not found] ` <43bd3f9d.71702a8b.4b407900.b542@o2.pl>
2010-01-03 21:49 ` Rafael J. Wysocki
2010-01-04 13:38 ` Stefan Seyfried
2010-01-03 21:33 ` Rafael J. Wysocki
2010-01-03 21:29 ` Rafael J. Wysocki
[not found] ` <24fb84fa.38887c91.4b411ffd.e7f1f@o2.pl>
2010-01-03 23:30 ` Rafael J. Wysocki
2010-01-03 23:35 ` Bartłomiej Zimoń [this message]
2010-01-03 23:45 ` Rafael J. Wysocki
2010-01-04 0:51 ` Bartłomiej Zimoń
2010-01-04 1:06 ` Bartłomiej Zimoń
2010-01-04 19:43 ` Rafael J. Wysocki
2010-01-05 9:07 ` [linux-pm] " Anders Eriksson
[not found] ` <7e89c5d.77f82021.4b43a8d7.127e1@o2.pl>
2010-01-05 21:23 ` Rafael J. Wysocki
2010-01-05 22:12 ` Bartłomiej Zimoń
2010-01-05 23:03 ` Rafael J. Wysocki
[not found] ` <1ab86ec9.7bc73105.4b43cd45.c2747@o2.pl>
2010-01-06 14:35 ` Anders Eriksson
2010-01-06 20:37 ` [linux-pm] [suspend/resume] Re: userspace notific ation " Bartłomiej Zimoń
2010-01-06 20:49 ` Roland Dreier
2010-01-06 20:56 ` Roland Dreier
2010-01-15 20:02 ` [linux-pm] [suspend/resume] Re: userspace notification " Pavel Machek
2010-01-05 21:26 ` Stefan Seyfried
[not found] ` <11f818a7.4b53f68a.4b43bb9b.b3a7f@o2.pl>
2010-01-05 23:05 ` Rafael J. Wysocki
2010-01-04 12:46 ` Daniel Borkmann
2010-01-04 19:45 ` Rafael J. Wysocki
2010-01-09 10:32 ` Pavel Machek
2010-01-09 13:40 ` Rafael J. Wysocki
2010-01-15 20:03 ` Pavel Machek
2010-01-15 22:14 ` Rafael J. Wysocki
2010-01-16 3:00 ` Eric Miao
2010-01-16 17:00 ` Stanislav Brabec
2010-01-16 18:12 ` Pavel Machek
2010-01-16 22:05 ` Rafael J. Wysocki
2010-01-16 22:19 ` Pavel Machek
2010-01-16 22:25 ` Pavel Machek
2010-01-16 22:31 ` Rafael J. Wysocki
2010-01-16 22:26 ` Rafael J. Wysocki
2010-01-17 13:07 ` Pavel Machek
2010-01-17 13:26 ` Russell King - ARM Linux
2010-01-19 5:15 ` Pavel Machek
2010-01-16 22:32 ` Russell King - ARM Linux
2010-01-16 18:12 ` Pavel Machek
2010-01-16 18:12 ` Pavel Machek
2010-01-16 22:07 ` Rafael J. Wysocki
2010-01-16 22:14 ` Pavel Machek
2010-01-16 22:21 ` Rafael J. Wysocki
2010-01-02 21:20 ` Bartłomiej Zimoń
2010-01-02 14:31 ` Bartłomiej Zimoń
2010-01-02 22:34 Bartłomiej Zimoń
2010-01-03 8:31 Bartłomiej Zimoń
2010-01-03 11:06 Bartłomiej Zimoń
2010-01-03 23:17 Bartłomiej Zimoń
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