From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Pavel Machek <pavel@ucw.cz>
Cc: "Bart?omiej Zimo?" <uzi18@o2.pl>, Andy Walls <awalls@radix.net>,
Daniel Borkmann <danborkmann@googlemail.com>,
linux-kernel@vger.kernel.org, rpurdie@rpsys.net,
lenz@cs.wisc.edu, Dirk@opfer-online.de, arminlitzel@web.de,
Cyril Hrubis <metan@ucw.cz>,
thommycheck@gmail.com,
"linux-arm-kernel" <linux-arm-kernel@lists.infradead.org>,
dbaryshkov@gmail.com, omegamoon@gmail.com, eric.y.miao@gmail.com,
utx@penguin.cz, zaurus-devel@www.linuxtogo.org
Subject: Re: [suspend/resume] Re: userspace notification from module
Date: Sat, 16 Jan 2010 23:07:48 +0100 [thread overview]
Message-ID: <201001162307.48085.rjw@sisk.pl> (raw)
In-Reply-To: <20100116181211.GA1603@ucw.cz>
On Saturday 16 January 2010, Pavel Machek wrote:
> Hi!
>
> > > > I wasn't aware of this.
> > > >
> > > > That may be a good reason for adding kernel-based suspend notification,
> > > > although I'd prefer ARM to notify the user space about the critical battery
> > > > status allowing it to decide what to do.
> > >
> > > Hard to do, without breaking compatibility that goes down to 2.4.X.
> >
> > Sending a battery-critical notification to the user space is not equivalent to
> > removing the existing kernel-based mechanism. They can exist both at the
> > same time if the notification is sent earlier than the kernel suspends
> > everything.
>
> Yes, and obviously sending notification early is ok with me.
>
> > > It really makes sense on zaurus. Those machines are simple, no
> > > smartbattery and no embedded controller subsystems. Battery will not
> > > protect itself, and its kernel job. (Should work on init=/bin/bash).
> > >
> > > As power-off consumption is same as suspend power consumption (I
> > > beleive zaurus simply does not have true power off), suspend on
> > > critical makes some sense. (Note that it is set lower than on pcs, and
> > > that we declare battery critical sooner than that.)
> >
> > The problem with that is it catches at least some applications unprepared and
> > notifying them that "we're suspending right now" doesn't really help, because
> > they won't have any time to react anyway.
>
> Agreed, but so what? On PC, machine would power off at that
> point. That would surprise the apps, too.
>
> Basically new enough userland should not make battery run low enough
> for either emergency power off or emergency suspend.
I wonder how it is supposed to achieve that without knowing the current battery
status. Do you mean it should poll the battery driver?
Rafael
next prev parent reply other threads:[~2010-01-16 22:07 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
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 [this message]
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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