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From: Boris Brezillon <boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
To: Sylvain Rochet <sylvain.rochet-ETtyaVkrhkNWk0Htik3J/w@public.gmane.org>
Cc: Andrew Victor <linux-PelNFVqkFnVyf+4FbqDuWQ@public.gmane.org>,
	Nicolas Ferre
	<nicolas.ferre-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org>,
	Jean-Christophe Plagniol-Villard
	<plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org>,
	voice.shen-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org,
	alexandre.belloni-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org,
	devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCHv2 1/2] dts: Documentation: AT91 Watchdog, explain what atmel,idle-halt property really do
Date: Thu, 22 Jan 2015 19:14:03 +0100	[thread overview]
Message-ID: <20150122191403.322059e3@bbrezillon> (raw)
In-Reply-To: <1421587611-32708-2-git-send-email-sylvain.rochet-ETtyaVkrhkNWk0Htik3J/w@public.gmane.org>

On Sun, 18 Jan 2015 14:26:50 +0100
Sylvain Rochet <sylvain.rochet-ETtyaVkrhkNWk0Htik3J/w@public.gmane.org> wrote:

> atmel,idle-halt property should be used with care, it actually makes the
> watchdog not counting when the CPU is in idle state, therefore the
> watchdog reset time depends on mean CPU usage and will not reset at all
> of the CPU stop working while it is in idle state, which is probably not
> what you want.
> 
> Signed-off-by: Sylvain Rochet <sylvain.rochet-ETtyaVkrhkNWk0Htik3J/w@public.gmane.org>

Acked-by: Boris Brezillon <boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>

> ---
>  Documentation/devicetree/bindings/watchdog/atmel-wdt.txt | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt b/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
> index f90e294..a4d8697 100644
> --- a/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
> +++ b/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
> @@ -26,6 +26,11 @@ Optional properties:
>  - atmel,disable : Should be present if you want to disable the watchdog.
>  - atmel,idle-halt : Should be present if you want to stop the watchdog when
>  	entering idle state.
> +	CAUTION: This property should be used with care, it actually makes the
> +	watchdog not counting when the CPU is in idle state, therefore the
> +	watchdog reset time depends on mean CPU usage and will not reset at all
> +	if the CPU stop working while it is in idle state, which is probably
> +	not what you want.
>  - atmel,dbg-halt : Should be present if you want to stop the watchdog when
>  	entering debug state.
>  



-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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  parent reply	other threads:[~2015-01-22 18:14 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-17 21:49 [PATCH] AT91: DT: Watchdog, remove property idle halt by default Sylvain Rochet
     [not found] ` <1421531396-20188-1-git-send-email-sylvain.rochet-ETtyaVkrhkNWk0Htik3J/w@public.gmane.org>
2015-01-18  8:08   ` Boris Brezillon
2015-01-18 13:26     ` [PATCHv2 0/2] dts: AT91 " Sylvain Rochet
     [not found]       ` <1421587611-32708-1-git-send-email-sylvain.rochet-ETtyaVkrhkNWk0Htik3J/w@public.gmane.org>
2015-01-18 13:26         ` [PATCHv2 1/2] dts: Documentation: AT91 Watchdog, explain what atmel,idle-halt property really do Sylvain Rochet
     [not found]           ` <1421587611-32708-2-git-send-email-sylvain.rochet-ETtyaVkrhkNWk0Htik3J/w@public.gmane.org>
2015-01-22 18:14             ` Boris Brezillon [this message]
2015-01-18 13:26         ` [PATCHv2 2/2] dts: AT91 Watchdog, remove property idle halt by default Sylvain Rochet

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