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From: mark gross <markgross@thegnar.org>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Raffaele Recalcati <lamiaposta71@gmail.com>,
	linux-pm@lists.linux-foundation.org,
	davinci-linux-open-source@linux.davincidsp.com,
	linux-kernel@vger.kernel.org
Subject: Re: [linux-pm] pm loss development
Date: Sat, 14 May 2011 09:35:13 -0700	[thread overview]
Message-ID: <20110514163513.GB8292@gvim.org> (raw)
In-Reply-To: <201105131854.57854.rjw@sisk.pl>

On Fri, May 13, 2011 at 06:54:57PM +0200, Rafael J. Wysocki wrote:
> On Friday, May 13, 2011, Raffaele Recalcati wrote:
> > Hi Rafael,
> > 
> > 2011/5/12 Rafael J. Wysocki <rjw@sisk.pl>:
> > > On Thursday, May 12, 2011, Raffaele Recalcati wrote:
> > >> What happen normally in runtime pm implementation is that every devices
> > >> are switched off and are enabled only when needed.
> > >> In our case instead we have a completely functional embedded system and,
> > >> when an asyncrhonous event appear, we have only some tens milliseconds
> > >> before the actual power failure takes place.
> > >> This patchset add a support in order to switch off not vital part of the system,
> > >> in order to allow the board to survive longer.
> > >> This allow the possibility to save important data.
> > >
> > > OK, so first, who decides what parts of the system are vital and what aren't?
> > 
> > Take a quick look at Documentation/power/loss.txt  paragrpah "2.4
> > Power loss policies".
> > You can decide what can be powered off.
> 
> I read the patches.  My question was about the general idea of who should
> be responsible of making these decisions.

I would expect the system integrator would based on the application the
device is getting deployed into.

A generic opportunistic policy for peripherals that are stateless and can
be trivially power gated off/on from an ISR could be a default but, for
peripherals that need to do some processing (like waiting on an eMMC DMA
to complete) can take time to power down into a safe state.

--mark

> 
> Thanks,
> Rafael
> _______________________________________________
> linux-pm mailing list
> linux-pm@lists.linux-foundation.org
> https://lists.linux-foundation.org/mailman/listinfo/linux-pm

  reply	other threads:[~2011-05-14 16:35 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-12 17:11 Raffaele Recalcati
2011-05-12 17:11 ` [PATCH 1/4] export bus_kset Raffaele Recalcati
2011-05-12 19:28   ` Rafael J. Wysocki
2011-05-13 17:11     ` Davide Ciminaghi
2011-05-15 14:13       ` [linux-pm] " Davide Ciminaghi
2011-05-17 23:04         ` Rafael J. Wysocki
2011-05-12 17:11 ` [PATCH 2/4] PM / Loss: power loss management Raffaele Recalcati
2011-05-12 19:57   ` Rafael J. Wysocki
2011-05-13 13:02     ` Davide Ciminaghi
2011-05-17 23:32       ` Rafael J. Wysocki
2011-05-19  9:26         ` Davide Ciminaghi
2011-05-19 14:25           ` [linux-pm] " Alan Stern
2011-05-19 20:52             ` Rafael J. Wysocki
2011-05-12 17:11 ` [PATCH 3/4] mmc: bus and block device drivers: support for pm_loss Raffaele Recalcati
2011-05-12 17:11 ` [PATCH 4/4] DaVinci: vpfe: " Raffaele Recalcati
2011-05-12 19:27 ` pm loss development Rafael J. Wysocki
2011-05-13  6:39   ` Raffaele Recalcati
2011-05-13 16:54     ` Rafael J. Wysocki
2011-05-14 16:35       ` mark gross [this message]
2011-05-17 23:07         ` [linux-pm] " Rafael J. Wysocki
2011-05-18  3:12           ` mark gross
2011-05-18 19:43             ` Rafael J. Wysocki
2011-05-18 22:17               ` Mark Brown
2011-05-19 12:45               ` mark gross
2011-06-02 22:21               ` Pavel Machek
2011-06-14 14:06                 ` mark gross
2011-06-14 14:36                   ` Alan Cox
2011-05-14 20:21       ` Raffaele Recalcati
2011-05-17 23:10         ` Rafael J. Wysocki
2011-05-14 18:53   ` [linux-pm] " Oliver Neukum
2011-05-14 20:34     ` Raffaele Recalcati
2011-05-17 23:06       ` Rafael J. Wysocki
2011-05-14 16:24 ` mark gross
2011-05-14 20:30   ` Raffaele Recalcati
2011-05-14 23:33     ` mark gross

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