From: pavel@ucw.cz (Pavel Machek)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 5/6] watchdog: at91sam9: request the irq with IRQF_NO_SUSPEND
Date: Sat, 7 Mar 2015 12:29:33 +0100 [thread overview]
Message-ID: <20150307112932.GA1372@amd> (raw)
In-Reply-To: <20150307110645.GW3989@piout.net>
On Sat 2015-03-07 12:06:45, Alexandre Belloni wrote:
> On 07/03/2015 at 11:39:39 +0100, Pavel Machek wrote :
> > > The Atmel watchdog can't be stopped once it's started. This is actually
> > > very useful so we can reset if suspend or resume failed, the only
> > > drawback is that you have to wake up from time to time (e.g. by using
> > > the RTC/RTT) to clear the watchdog and then go back to sleep ASAP.
> >
> > Yeah. So you do "echo mem > /sys/power/state", and few seconds/minutes
> > after watchdog kills the system. But you did not ask for dead system,
> > you asked for suspend.
> >
> > And while that behaviour is useful for you, I don't think it is
> > exactly useful behaviour, nor it is the behaviour user would expect.
> >
>
> I think you misunderstood, that is exactly the expected behaviour. This
> is hardware defined. Once the watchdog is started, nobody can stop it.
> Trying to change the mode register will result in a reset of the
> SoC.
Well, it boils down to "what is stronger". Desire to suspend the
system, or desire to reboot the system.
It is "echo mem > state", not "echo reboot > state".
> It is documented in the datasheet and any user wanting another behaviour
> is out of luck.
Actaully, your platform should just refuse to enter suspend-to-RAM
when hw watchdog is enabled.
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:[~2015-03-07 11:29 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-02 9:18 [PATCH v2 0/6] ARM: at91: fix irq_pm_install_action WARNING Boris Brezillon
2015-03-02 9:18 ` [PATCH v2 1/6] PM / wakeup: export pm_system_wakeup symbol Boris Brezillon
2015-03-02 9:18 ` [PATCH v2 2/6] rtc: at91sam9: rework wakeup and interrupt handling Boris Brezillon
2015-03-04 18:23 ` Mark Rutland
2015-03-02 9:18 ` [PATCH v2 3/6] rtc: at91rm9200: " Boris Brezillon
2015-03-02 9:18 ` [PATCH v2 4/6] clk: at91: implement suspend/resume for the PMC irqchip Boris Brezillon
2015-03-09 22:34 ` Mike Turquette
2015-03-02 9:18 ` [PATCH v2 5/6] watchdog: at91sam9: request the irq with IRQF_NO_SUSPEND Boris Brezillon
2015-03-02 14:10 ` Guenter Roeck
2015-03-04 18:38 ` Mark Rutland
2015-03-04 21:41 ` Rafael J. Wysocki
2015-03-05 10:57 ` Mark Rutland
2015-03-05 15:10 ` Rafael J. Wysocki
2015-03-05 16:32 ` Mark Rutland
2015-03-06 0:29 ` Rafael J. Wysocki
2015-03-06 11:06 ` Mark Rutland
2015-03-06 12:39 ` Rafael J. Wysocki
2015-03-06 13:10 ` Mark Rutland
2015-03-07 9:12 ` Peter Zijlstra
2015-03-07 9:06 ` Peter Zijlstra
2015-03-05 8:53 ` Boris Brezillon
2015-03-05 10:53 ` Mark Rutland
2015-03-05 11:17 ` Boris Brezillon
2015-03-05 11:31 ` Boris Brezillon
2015-03-05 11:53 ` Mark Rutland
2015-03-07 9:18 ` Peter Zijlstra
2015-03-07 10:20 ` Sylvain Rochet
2015-03-07 10:39 ` Pavel Machek
2015-03-07 10:59 ` Sylvain Rochet
2015-03-07 11:06 ` Alexandre Belloni
2015-03-07 11:29 ` Pavel Machek [this message]
2015-03-07 11:46 ` Sylvain Rochet
2015-03-08 1:12 ` Rafael J. Wysocki
2015-03-09 7:55 ` Alexandre Belloni
2015-03-09 14:30 ` Rafael J. Wysocki
2015-03-10 21:33 ` Alexandre Belloni
2015-03-10 22:31 ` Rafael J. Wysocki
2015-03-10 22:33 ` Alexandre Belloni
2015-03-11 1:03 ` Rafael J. Wysocki
2015-03-11 7:33 ` Boris Brezillon
2015-03-08 1:11 ` Rafael J. Wysocki
2015-03-11 8:38 ` Boris Brezillon
2015-03-11 11:17 ` Nicolas Ferre
2015-03-02 9:18 ` [PATCH v2 6/6] tty: serial: atmel: rework interrupt and wakeup handling Boris Brezillon
2015-03-03 8:56 ` [PATCH v2 0/6] ARM: at91: fix irq_pm_install_action WARNING Alexandre Belloni
2015-03-03 15:35 ` Nicolas Ferre
2015-03-04 1:43 ` Rafael J. Wysocki
2015-03-04 18:43 ` Mark Rutland
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20150307112932.GA1372@amd \
--to=pavel@ucw.cz \
--cc=linux-arm-kernel@lists.infradead.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).