From: Pavel Machek <pavel@ucw.cz>
To: Arve Hj?nnev?g <arve@android.com>
Cc: ncunningham@crca.org.au, u.luckas@road.de, swetland@google.com,
linux-pm@lists.linux-foundation.org
Subject: Re: [PATCH 01/13] PM: Add wake lock api.
Date: Sun, 8 Feb 2009 22:21:22 +0100 [thread overview]
Message-ID: <20090208212122.GG6369@elf.ucw.cz> (raw)
In-Reply-To: <d6200be20902071620o2012e80es272745f98345b656@mail.gmail.com>
Hi!
> >> > If my understanding is correct, a wakelock is a mechanism that, if held, will
> >> > prevent the system from (automatically) entering a sleep state, but why do we
> >> > need a number of such wakelocks instead of just one reference counter with the
> >> > rule that (automatic) suspend can only happen if the counter is zero?
> >>
> >> Using wakelocks instead of a global reference count ensures that your
> >> request cannot be cleared by someone else.
> >
> > Decreasing the refcount without increasing it would have been a bug, IMO.
>
> Yes, but if all you have is a global reference count, you can't tell
> where the bug is.
...
> >> and detailed stats.
> >
> > Well, I'm not sure how this is useful in the long run.
>
> You may want to know which app drained your battery.
_If_ we want to allow userspace to hold wakelocks (better name could
be awakelock or nosleeplock?) then some way of displaying them is
required.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
next prev parent reply other threads:[~2009-02-08 21:21 UTC|newest]
Thread overview: 192+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-05 2:50 [RFC][PATCH 00/11] Android PM extensions Arve Hjønnevåg
2009-02-05 2:50 ` [PATCH 01/13] PM: Add wake lock api Arve Hjønnevåg
2009-02-05 2:50 ` [PATCH 02/13] PM: Add early suspend api Arve Hjønnevåg
2009-02-05 2:50 ` [PATCH 03/13] PM: Implement wakelock api Arve Hjønnevåg
2009-02-05 2:50 ` [PATCH 04/13] PM: wakelock: Override wakelocks when using /sys/power/state Arve Hjønnevåg
2009-02-05 2:50 ` [PATCH 05/13] PM: Add option to disable /sys/power/state interface Arve Hjønnevåg
2009-02-05 2:50 ` [PATCH 06/13] PM: Implement early suspend api Arve Hjønnevåg
2009-02-05 2:50 ` [PATCH 07/13] PM: wakelock: Add /sys/power/request_state Arve Hjønnevåg
2009-02-05 2:50 ` [PATCH 08/13] PM: Add user-space wake lock api Arve Hjønnevåg
2009-02-05 2:50 ` [PATCH 09/13] PM: wakelock: Abort task freezing if a wake lock is held Arve Hjønnevåg
2009-02-05 2:50 ` [PATCH 10/13] PM: earlysuspend: Add console switch when user requested sleep state changes Arve Hjønnevåg
2009-02-05 2:50 ` [PATCH 11/13] PM: earlysuspend: Removing dependence on console Arve Hjønnevåg
2009-02-05 2:50 ` [PATCH 12/13] Input: Hold wake lock while event queue is not empty Arve Hjønnevåg
2009-02-05 2:50 ` [PATCH 13/13] ledtrig-sleep: Add led trigger for sleep debugging Arve Hjønnevåg
2009-02-05 9:08 ` [PATCH 12/13] Input: Hold wake lock while event queue is not empty Pavel Machek
2009-02-05 9:06 ` [PATCH 11/13] PM: earlysuspend: Removing dependence on console Pavel Machek
2009-02-05 9:42 ` Arve Hjønnevåg
2009-02-05 9:53 ` Pavel Machek
2009-02-05 9:03 ` [PATCH 10/13] PM: earlysuspend: Add console switch when user requested sleep state changes Pavel Machek
2009-02-05 9:37 ` Arve Hjønnevåg
2009-02-05 9:51 ` Pavel Machek
2009-02-05 10:54 ` Uli Luckas
2009-02-06 2:29 ` Arve Hjønnevåg
2009-02-08 22:02 ` Pavel Machek
2009-02-08 22:53 ` Arve Hjønnevåg
2009-02-08 22:58 ` Pavel Machek
2009-02-05 8:55 ` [PATCH 09/13] PM: wakelock: Abort task freezing if a wake lock is held Pavel Machek
2009-02-05 9:30 ` Arve Hjønnevåg
2009-02-05 9:49 ` Pavel Machek
2009-02-05 9:58 ` Arve Hjønnevåg
2009-02-05 10:02 ` Pavel Machek
2009-02-05 10:08 ` Arve Hjønnevåg
2009-02-06 3:42 ` Arve Hjønnevåg
2009-02-08 23:00 ` Pavel Machek
2009-02-06 0:35 ` mark gross
2009-02-05 8:53 ` [PATCH 08/13] PM: Add user-space wake lock api Pavel Machek
2009-02-05 8:52 ` [PATCH 07/13] PM: wakelock: Add /sys/power/request_state Pavel Machek
2009-02-05 9:25 ` Arve Hjønnevåg
2009-02-05 9:27 ` Pavel Machek
2009-02-07 22:54 ` Rafael J. Wysocki
2009-02-06 0:18 ` [PATCH 06/13] PM: Implement early suspend api mark gross
2009-02-07 22:47 ` Rafael J. Wysocki
2009-02-08 2:32 ` Benjamin Herrenschmidt
2009-02-08 13:33 ` Rafael J. Wysocki
2009-02-05 9:17 ` [PATCH 05/13] PM: Add option to disable /sys/power/state interface Pavel Machek
2009-02-07 22:37 ` Rafael J. Wysocki
2009-02-08 10:33 ` Pavel Machek
2009-02-08 13:50 ` Rafael J. Wysocki
2009-02-08 14:04 ` Brian Swetland
2009-02-08 21:06 ` Pavel Machek
2009-02-08 23:41 ` Rafael J. Wysocki
2009-02-09 1:58 ` Uli Luckas
2009-02-10 0:09 ` Rafael J. Wysocki
2009-02-08 23:40 ` Rafael J. Wysocki
2009-02-08 23:58 ` Arve Hjønnevåg
2009-02-09 0:26 ` Rafael J. Wysocki
2009-02-09 1:35 ` Arve Hjønnevåg
2009-02-09 1:53 ` Brian Swetland
2009-02-09 8:58 ` Pavel Machek
2009-02-09 13:31 ` Brian Swetland
2009-02-10 11:19 ` Pavel Machek
2009-02-09 9:15 ` Pavel Machek
2009-02-09 3:07 ` Alan Stern
2009-02-11 22:26 ` Rafael J. Wysocki
2009-02-09 9:09 ` Pavel Machek
2009-02-12 11:16 ` Matthew Garrett
2009-02-08 21:04 ` Pavel Machek
2009-02-08 21:40 ` Alan Stern
2009-02-08 23:00 ` Arve Hjønnevåg
2009-02-08 23:03 ` Pavel Machek
2009-02-09 0:31 ` Rafael J. Wysocki
2009-02-09 2:11 ` Uli Luckas
2009-02-09 2:24 ` Arve Hjønnevåg
2009-02-09 2:56 ` Uli Luckas
2009-02-09 9:01 ` Pavel Machek
2009-02-10 0:17 ` Rafael J. Wysocki
2009-02-10 9:13 ` Pavel Machek
2009-02-10 14:18 ` Rafael J. Wysocki
2009-02-08 23:41 ` Pavel Machek
2009-02-08 23:44 ` Rafael J. Wysocki
2009-02-08 23:44 ` Rafael J. Wysocki
2009-02-07 22:31 ` [PATCH 04/13] PM: wakelock: Override wakelocks when using /sys/power/state Rafael J. Wysocki
2009-02-05 9:16 ` [PATCH 03/13] PM: Implement wakelock api Pavel Machek
2009-02-05 15:24 ` Alan Stern
2009-02-06 0:10 ` mark gross
2009-02-06 0:38 ` Arve Hjønnevåg
2009-02-07 0:33 ` mark gross
2009-02-07 0:47 ` Arve Hjønnevåg
2009-02-09 18:00 ` mark gross
2009-02-10 20:24 ` Pavel Machek
2009-02-07 22:27 ` Rafael J. Wysocki
2009-02-11 2:52 ` Arve Hjønnevåg
2009-02-05 9:14 ` [PATCH 02/13] PM: Add early suspend api Pavel Machek
2009-02-05 23:26 ` mark gross
2009-02-06 9:33 ` Uli Luckas
2009-02-06 23:26 ` Arve Hjønnevåg
2009-02-07 20:53 ` Rafael J. Wysocki
2009-02-07 23:34 ` Arve Hjønnevåg
2009-02-08 20:59 ` Pavel Machek
2009-02-08 23:59 ` Rafael J. Wysocki
2009-02-05 9:11 ` [PATCH 01/13] PM: Add wake lock api Pavel Machek
2009-02-06 0:28 ` Arve Hjønnevåg
2009-02-06 9:45 ` Uli Luckas
2009-02-08 21:30 ` Pavel Machek
2009-02-08 23:11 ` Arve Hjønnevåg
2009-02-09 9:06 ` Pavel Machek
2009-02-08 22:17 ` non-racy examples, please (was Re: [PATCH 01/13] PM: Add wake lock api.) Pavel Machek
2009-02-08 22:40 ` Arve Hjønnevåg
2009-02-08 23:14 ` Pavel Machek
2009-02-08 23:35 ` Arve Hjønnevåg
2009-02-10 11:15 ` Pavel Machek
2009-02-11 3:12 ` Arve Hjønnevåg
2009-02-09 1:49 ` non-racy examples, please (was Re: [PATCH 01/13] PM: Add wake lock api. ) Uli Luckas
2009-02-10 11:17 ` non-racy examples, please (was Re: [PATCH 01/13] PM: Add wake lock?api.) Pavel Machek
2009-02-10 12:10 ` Woodruff, Richard
2009-02-10 13:14 ` Pavel Machek
2009-02-10 13:20 ` Woodruff, Richard
2009-02-10 13:42 ` Brian Swetland
2009-02-10 12:35 ` Uli Luckas
2009-02-06 1:32 ` [PATCH 01/13] PM: Add wake lock api mark gross
2009-02-05 22:51 ` mark gross
2009-02-06 0:13 ` Arve Hjønnevåg
2009-02-10 20:25 ` Pavel Machek
2009-02-11 2:11 ` Arve Hjønnevåg
2009-02-11 4:47 ` Brian Swetland
2009-02-11 8:40 ` Uli Luckas
2009-02-11 14:58 ` Alan Stern
2009-02-11 15:45 ` Rafael J. Wysocki
2009-02-08 22:57 ` Pavel Machek
2009-02-11 21:37 ` Pavel Machek
2009-02-11 22:05 ` Alan Stern
2009-02-11 23:55 ` Arve Hjønnevåg
2009-02-12 18:47 ` mark gross
2009-02-07 18:56 ` Rafael J. Wysocki
2009-02-07 22:51 ` Arve Hjønnevåg
2009-02-07 23:25 ` Rafael J. Wysocki
2009-02-08 0:20 ` Arve Hjønnevåg
2009-02-08 21:21 ` Pavel Machek [this message]
2009-02-09 0:03 ` Rafael J. Wysocki
2009-02-09 0:15 ` Rafael J. Wysocki
2009-02-09 2:03 ` Arve Hjønnevåg
2009-02-11 22:23 ` Rafael J. Wysocki
2009-02-11 23:42 ` Arve Hjønnevåg
2009-02-12 22:22 ` Rafael J. Wysocki
2009-02-12 23:42 ` Woodruff, Richard
2009-02-13 1:10 ` Matthew Garrett
2009-02-13 2:21 ` Arve Hjønnevåg
2009-02-13 2:40 ` Nigel Cunningham
2009-02-13 3:17 ` Woodruff, Richard
2009-02-13 10:55 ` Uli Luckas
2009-02-13 14:06 ` Matthew Garrett
2009-02-13 14:24 ` Brian Swetland
2009-02-13 14:37 ` Matthew Garrett
2009-02-13 14:46 ` Brian Swetland
2009-02-13 15:07 ` Matthew Garrett
2009-02-13 22:52 ` Rafael J. Wysocki
2009-02-13 16:46 ` Uli Luckas
2009-02-13 17:05 ` Matthew Garrett
2009-02-13 18:13 ` Uli Luckas
2009-02-13 19:14 ` Matthew Garrett
2009-02-13 19:35 ` Uli Luckas
2009-02-13 16:49 ` Uli Luckas
2009-02-13 17:09 ` Matthew Garrett
2009-02-13 18:18 ` Uli Luckas
2009-02-27 13:18 ` Pavel Machek
2009-02-27 14:07 ` Uli Luckas
2009-02-27 20:32 ` Pavel Machek
2009-03-02 13:53 ` Uli Luckas
2009-03-03 14:02 ` Pavel Machek
2009-03-04 13:41 ` Uli Luckas
2009-03-04 14:00 ` Uli Luckas
2009-03-04 14:13 ` Pavel Machek
2009-03-04 14:34 ` Uli Luckas
2009-03-04 17:10 ` Pavel Machek
2009-03-05 17:42 ` Uli Luckas
2009-03-08 8:32 ` Pavel Machek
2009-03-08 12:34 ` Alan Stern
2009-02-13 23:36 ` Arve Hjønnevåg
2009-02-14 0:05 ` Matthew Garrett
2009-02-14 0:50 ` Arve Hjønnevåg
2009-02-14 1:06 ` Matthew Garrett
2009-02-14 1:33 ` Arve Hjønnevåg
2009-02-14 1:49 ` Matthew Garrett
2009-02-14 5:51 ` Arve Hjønnevåg
2009-02-14 20:44 ` Matthew Garrett
2009-02-26 15:04 ` Pavel Machek
2009-02-26 21:11 ` Arve Hjønnevåg
2009-02-26 21:36 ` Pavel Machek
2009-02-27 0:16 ` Arve Hjønnevåg
2009-02-27 9:56 ` Pavel Machek
2009-02-28 3:20 ` Arve Hjønnevåg
2009-02-06 23:51 ` [RFC][PATCH 00/11] Android PM extensions Rafael J. Wysocki
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