From: Alexandre Belloni <alexandre.belloni@free-electrons.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Pavel Machek <pavel@ucw.cz>,
Sylvain Rochet <gradator@gradator.net>,
Peter Zijlstra <peterz@infradead.org>,
Mark Rutland <mark.rutland@arm.com>,
Boris Brezillon <boris.brezillon@free-electrons.com>,
Alessandro Zummo <a.zummo@towertech.it>,
Mike Turquette <mturquette@linaro.org>,
Jason Cooper <jason@lakedaemon.net>,
"rtc-linux@googlegroups.com" <rtc-linux@googlegroups.com>,
Len Brown <len.brown@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Nicolas Ferre <nicolas.ferre@atmel.com>,
Wim Van Sebroeck <wim@iguana.be>,
"linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>,
Thomas Gleixner <tglx@linutronix.de>, Jiri Slaby <jslaby@suse.cz>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 5/6] watchdog: at91sam9: request the irq with IRQF_NO_SUSPEND
Date: Mon, 9 Mar 2015 08:55:46 +0100 [thread overview]
Message-ID: <20150309075546.GY3989@piout.net> (raw)
In-Reply-To: <1615214.0rkGfM1gZL@vostro.rjw.lan>
Hi,
On 08/03/2015 at 02:12:53 +0100, Rafael J. Wysocki wrote :
> > > 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.
>
> Quite likely, depending on how exactly the suspend is implemented.
>
We've had absolutely zero complain on that. It is quite clear in the
datasheet that failing to refresh the watchdog once started will lead to
a reset and that it is impossible to stop.
It is actually quite convenient to also ensure that you can actually
wake up from suspend because that can obviously go wrong.
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
WARNING: multiple messages have this Message-ID (diff)
From: Alexandre Belloni <alexandre.belloni@free-electrons.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Pavel Machek <pavel@ucw.cz>,
Sylvain Rochet <gradator@gradator.net>,
Peter Zijlstra <peterz@infradead.org>,
Mark Rutland <mark.rutland@arm.com>,
Boris Brezillon <boris.brezillon@free-electrons.com>,
Alessandro Zummo <a.zummo@towertech.it>,
Mike Turquette <mturquette@linaro.org>,
Jason Cooper <jason@lakedaemon.net>,
"rtc-linux@googlegroups.com" <rtc-linux@googlegroups.com>,
Len Brown <len.brown@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Nicolas Ferre <nicolas.ferre@atmel.com>,
Wim Van Sebroeck <wim@iguana.be>,
"linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>,
Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>,
Thomas Gleixner <tglx@linutronix.de>, Jiri Slaby <jslaby@suse.cz>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-watchdog@vger.kernel.org" <linux-watchdog@vger.kernel.org>
Subject: Re: [PATCH v2 5/6] watchdog: at91sam9: request the irq with IRQF_NO_SUSPEND
Date: Mon, 9 Mar 2015 08:55:46 +0100 [thread overview]
Message-ID: <20150309075546.GY3989@piout.net> (raw)
In-Reply-To: <1615214.0rkGfM1gZL@vostro.rjw.lan>
Hi,
On 08/03/2015 at 02:12:53 +0100, Rafael J. Wysocki wrote :
> > > 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.
>
> Quite likely, depending on how exactly the suspend is implemented.
>
We've had absolutely zero complain on that. It is quite clear in the
datasheet that failing to refresh the watchdog once started will lead to
a reset and that it is impossible to stop.
It is actually quite convenient to also ensure that you can actually
wake up from suspend because that can obviously go wrong.
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
WARNING: multiple messages have this Message-ID (diff)
From: alexandre.belloni@free-electrons.com (Alexandre Belloni)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 5/6] watchdog: at91sam9: request the irq with IRQF_NO_SUSPEND
Date: Mon, 9 Mar 2015 08:55:46 +0100 [thread overview]
Message-ID: <20150309075546.GY3989@piout.net> (raw)
In-Reply-To: <1615214.0rkGfM1gZL@vostro.rjw.lan>
Hi,
On 08/03/2015 at 02:12:53 +0100, Rafael J. Wysocki wrote :
> > > 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.
>
> Quite likely, depending on how exactly the suspend is implemented.
>
We've had absolutely zero complain on that. It is quite clear in the
datasheet that failing to refresh the watchdog once started will lead to
a reset and that it is impossible to stop.
It is actually quite convenient to also ensure that you can actually
wake up from suspend because that can obviously go wrong.
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
next prev parent reply other threads:[~2015-03-09 7:55 UTC|newest]
Thread overview: 144+ 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 ` Boris Brezillon
2015-03-02 9:18 ` 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 ` Boris Brezillon
2015-03-02 9:18 ` [PATCH v2 3/6] rtc: at91rm9200: rework wakeup and interrupt handling Boris Brezillon
2015-03-02 9:18 ` Boris Brezillon
2015-03-02 9:18 ` [PATCH v2 4/6] clk: at91: implement suspend/resume for the PMC irqchip Boris Brezillon
2015-03-02 9:18 ` Boris Brezillon
2015-03-02 9:18 ` Boris Brezillon
[not found] ` <1425287898-15093-5-git-send-email-boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
2015-03-09 22:34 ` Mike Turquette
2015-03-09 22:34 ` Mike Turquette
2015-03-09 22:34 ` Mike Turquette
2015-03-09 22:34 ` Mike Turquette
2015-03-02 9:18 ` [PATCH v2 6/6] tty: serial: atmel: rework interrupt and wakeup handling Boris Brezillon
2015-03-02 9:18 ` Boris Brezillon
[not found] ` <1425287898-15093-1-git-send-email-boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
2015-03-02 9:18 ` [PATCH v2 2/6] rtc: at91sam9: rework wakeup and interrupt handling Boris Brezillon
2015-03-02 9:18 ` Boris Brezillon
2015-03-02 9:18 ` Boris Brezillon
[not found] ` <1425287898-15093-3-git-send-email-boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
2015-03-04 18:23 ` Mark Rutland
2015-03-04 18:23 ` Mark Rutland
2015-03-04 18:23 ` Mark Rutland
2015-03-02 9:18 ` [PATCH v2 5/6] watchdog: at91sam9: request the irq with IRQF_NO_SUSPEND Boris Brezillon
2015-03-02 9:18 ` Boris Brezillon
2015-03-02 9:18 ` Boris Brezillon
2015-03-02 14:10 ` Guenter Roeck
2015-03-02 14:10 ` Guenter Roeck
[not found] ` <1425287898-15093-6-git-send-email-boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
2015-03-04 18:38 ` Mark Rutland
2015-03-04 18:38 ` Mark Rutland
2015-03-04 18:38 ` Mark Rutland
2015-03-04 21:41 ` Rafael J. Wysocki
2015-03-04 21:41 ` Rafael J. Wysocki
2015-03-04 21:41 ` Rafael J. Wysocki
[not found] ` <14143668.0aRkeVrc3Q-sKB8Sp2ER+y1GS7QM15AGw@public.gmane.org>
2015-03-05 10:57 ` Mark Rutland
2015-03-05 10:57 ` Mark Rutland
2015-03-05 10:57 ` Mark Rutland
2015-03-05 15:10 ` Rafael J. Wysocki
2015-03-05 15:10 ` Rafael J. Wysocki
2015-03-05 15:10 ` Rafael J. Wysocki
[not found] ` <CAJZ5v0h8vn26BeWPVhC4e_KNhBu15-mshnbq0K=OQ1M36vPQEQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-03-05 16:32 ` Mark Rutland
2015-03-05 16:32 ` Mark Rutland
2015-03-05 16:32 ` Mark Rutland
2015-03-06 0:29 ` Rafael J. Wysocki
2015-03-06 0:29 ` Rafael J. Wysocki
2015-03-06 0:29 ` Rafael J. Wysocki
2015-03-06 11:06 ` Mark Rutland
2015-03-06 11:06 ` Mark Rutland
2015-03-06 11:06 ` Mark Rutland
2015-03-06 12:39 ` Rafael J. Wysocki
2015-03-06 12:39 ` Rafael J. Wysocki
2015-03-06 12:39 ` Rafael J. Wysocki
[not found] ` <CAJZ5v0jA-hRUnP_+mOdFw7vN7CGZ4o0FjUVu81rq7foi92f63g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-03-06 13:10 ` Mark Rutland
2015-03-06 13:10 ` Mark Rutland
2015-03-06 13:10 ` Mark Rutland
2015-03-07 9:12 ` Peter Zijlstra
2015-03-07 9:12 ` Peter Zijlstra
2015-03-07 9:12 ` Peter Zijlstra
2015-03-07 9:06 ` Peter Zijlstra
2015-03-07 9:06 ` Peter Zijlstra
2015-03-07 9:06 ` Peter Zijlstra
2015-03-05 8:53 ` Boris Brezillon
2015-03-05 8:53 ` Boris Brezillon
2015-03-05 8:53 ` Boris Brezillon
2015-03-05 10:53 ` Mark Rutland
2015-03-05 10:53 ` Mark Rutland
2015-03-05 10:53 ` Mark Rutland
2015-03-05 11:17 ` Boris Brezillon
2015-03-05 11:17 ` Boris Brezillon
2015-03-05 11:17 ` Boris Brezillon
2015-03-05 11:31 ` Boris Brezillon
2015-03-05 11:31 ` Boris Brezillon
2015-03-05 11:31 ` Boris Brezillon
2015-03-05 11:53 ` Mark Rutland
2015-03-05 11:53 ` Mark Rutland
2015-03-05 11:53 ` Mark Rutland
2015-03-07 9:18 ` Peter Zijlstra
2015-03-07 9:18 ` Peter Zijlstra
2015-03-07 9:18 ` Peter Zijlstra
2015-03-07 10:20 ` Sylvain Rochet
2015-03-07 10:20 ` Sylvain Rochet
2015-03-07 10:20 ` Sylvain Rochet
2015-03-07 10:39 ` Pavel Machek
2015-03-07 10:39 ` Pavel Machek
2015-03-07 10:39 ` Pavel Machek
2015-03-07 10:59 ` Sylvain Rochet
2015-03-07 10:59 ` Sylvain Rochet
2015-03-07 10:59 ` Sylvain Rochet
2015-03-07 11:06 ` Alexandre Belloni
2015-03-07 11:06 ` Alexandre Belloni
2015-03-07 11:06 ` Alexandre Belloni
[not found] ` <20150307110645.GW3989-m++hUPXGwpdeoWH0uzbU5w@public.gmane.org>
2015-03-07 11:29 ` Pavel Machek
2015-03-07 11:29 ` Pavel Machek
2015-03-07 11:29 ` Pavel Machek
2015-03-07 11:46 ` Sylvain Rochet
2015-03-07 11:46 ` Sylvain Rochet
2015-03-07 11:46 ` Sylvain Rochet
2015-03-08 1:12 ` Rafael J. Wysocki
2015-03-08 1:12 ` Rafael J. Wysocki
2015-03-08 1:12 ` Rafael J. Wysocki
2015-03-09 7:55 ` Alexandre Belloni [this message]
2015-03-09 7:55 ` Alexandre Belloni
2015-03-09 7:55 ` Alexandre Belloni
2015-03-09 14:30 ` Rafael J. Wysocki
2015-03-09 14:30 ` Rafael J. Wysocki
2015-03-09 14:30 ` Rafael J. Wysocki
[not found] ` <1592385.fqRVVyPSPE-sKB8Sp2ER+y1GS7QM15AGw@public.gmane.org>
2015-03-10 21:33 ` Alexandre Belloni
2015-03-10 21:33 ` Alexandre Belloni
2015-03-10 21:33 ` Alexandre Belloni
2015-03-10 22:31 ` Rafael J. Wysocki
2015-03-10 22:31 ` Rafael J. Wysocki
2015-03-10 22:31 ` Rafael J. Wysocki
[not found] ` <1901056.Mqyykpv3e9-sKB8Sp2ER+y1GS7QM15AGw@public.gmane.org>
2015-03-10 22:33 ` Alexandre Belloni
2015-03-10 22:33 ` Alexandre Belloni
2015-03-10 22:33 ` Alexandre Belloni
[not found] ` <20150310223305.GN9188-m++hUPXGwpdeoWH0uzbU5w@public.gmane.org>
2015-03-11 1:03 ` Rafael J. Wysocki
2015-03-11 1:03 ` Rafael J. Wysocki
2015-03-11 1:03 ` Rafael J. Wysocki
2015-03-11 7:33 ` Boris Brezillon
2015-03-11 7:33 ` Boris Brezillon
2015-03-11 7:33 ` Boris Brezillon
2015-03-08 1:11 ` Rafael J. Wysocki
2015-03-08 1:11 ` Rafael J. Wysocki
2015-03-08 1:11 ` Rafael J. Wysocki
2015-03-11 8:38 ` Boris Brezillon
2015-03-11 8:38 ` Boris Brezillon
2015-03-11 8:38 ` Boris Brezillon
2015-03-11 11:17 ` Nicolas Ferre
2015-03-11 11:17 ` Nicolas Ferre
2015-03-11 11:17 ` Nicolas Ferre
2015-03-11 11:17 ` Nicolas Ferre
2015-03-03 8:56 ` [PATCH v2 0/6] ARM: at91: fix irq_pm_install_action WARNING Alexandre Belloni
2015-03-03 8:56 ` Alexandre Belloni
2015-03-03 8:56 ` Alexandre Belloni
2015-03-03 15:35 ` Nicolas Ferre
2015-03-03 15:35 ` Nicolas Ferre
2015-03-03 15:35 ` Nicolas Ferre
2015-03-03 15:35 ` Nicolas Ferre
2015-03-04 1:43 ` Rafael J. Wysocki
2015-03-04 1:43 ` Rafael J. Wysocki
2015-03-04 1:43 ` Rafael J. Wysocki
2015-03-04 1:43 ` Rafael J. Wysocki
2015-03-04 18:43 ` Mark Rutland
2015-03-04 18:43 ` Mark Rutland
2015-03-04 18:43 ` Mark Rutland
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