From: andrew@lunn.ch (Andrew Lunn)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] cpuidle: kirkwood: Move out of mach directory, add DT.
Date: Fri, 28 Dec 2012 18:56:18 +0100 [thread overview]
Message-ID: <20121228175618.GC7578@lunn.ch> (raw)
In-Reply-To: <50DDDBEB.3000002@ti.com>
> Is this single CPU or multi-cpu machine ?
Its a uniprocessor.
> Even though the cpu_do_idle()
> has just couple of instructions, there can be lot more happening in
> background especially with multi masters system. It might be safe if the
> single CPU is the only master accessing DDR. In multi-master, multi-CPU
> scenario though it can't work reliably.
There are DMA engines which could be active, moving stuff into/out of
memory.
Having said that, this code is not new, it is just getting a new home.
There has not been problems before. Having this 256 cycle delay etc,
suggests the hardware design is robust.
Andrew
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Lunn <andrew-g2DYL2Zd6BY@public.gmane.org>
To: Santosh Shilimkar <santosh.shilimkar-l0cyMroinI0@public.gmane.org>
Cc: Andrew Lunn <andrew-g2DYL2Zd6BY@public.gmane.org>,
Jason Cooper <jason-NLaQJdtUoK4Be96aLqz0jA@public.gmane.org>,
len.brown-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org,
rafael.j.wysocki-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org,
linux ARM
<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>
Subject: Re: [PATCH] cpuidle: kirkwood: Move out of mach directory, add DT.
Date: Fri, 28 Dec 2012 18:56:18 +0100 [thread overview]
Message-ID: <20121228175618.GC7578@lunn.ch> (raw)
In-Reply-To: <50DDDBEB.3000002-l0cyMroinI0@public.gmane.org>
> Is this single CPU or multi-cpu machine ?
Its a uniprocessor.
> Even though the cpu_do_idle()
> has just couple of instructions, there can be lot more happening in
> background especially with multi masters system. It might be safe if the
> single CPU is the only master accessing DDR. In multi-master, multi-CPU
> scenario though it can't work reliably.
There are DMA engines which could be active, moving stuff into/out of
memory.
Having said that, this code is not new, it is just getting a new home.
There has not been problems before. Having this 256 cycle delay etc,
suggests the hardware design is robust.
Andrew
next prev parent reply other threads:[~2012-12-28 17:56 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-28 12:47 [PATCH] cpuidle: kirkwood: Move out of mach directory, add DT Andrew Lunn
2012-12-28 12:47 ` Andrew Lunn
2012-12-28 14:18 ` Rob Herring
2012-12-28 14:18 ` Rob Herring
2012-12-28 14:35 ` Andrew Lunn
2012-12-28 14:35 ` Andrew Lunn
2012-12-28 14:55 ` Rob Herring
2012-12-28 14:55 ` Rob Herring
2012-12-28 15:49 ` Andrew Lunn
2012-12-28 15:49 ` Andrew Lunn
2012-12-28 16:14 ` Rob Herring
2012-12-28 16:14 ` Rob Herring
2012-12-28 16:38 ` Andrew Lunn
2012-12-28 16:38 ` Andrew Lunn
2012-12-28 16:59 ` Rob Herring
2012-12-28 16:59 ` Rob Herring
2012-12-28 16:56 ` Santosh Shilimkar
2012-12-28 16:56 ` Santosh Shilimkar
2012-12-28 17:28 ` Andrew Lunn
2012-12-28 17:28 ` Andrew Lunn
2012-12-28 17:50 ` Santosh Shilimkar
2012-12-28 17:50 ` Santosh Shilimkar
2012-12-28 17:56 ` Andrew Lunn [this message]
2012-12-28 17:56 ` Andrew Lunn
2012-12-28 18:02 ` Santosh Shilimkar
2012-12-28 18:02 ` Santosh Shilimkar
2012-12-28 14:32 ` Florian Fainelli
2012-12-28 14:32 ` Florian Fainelli
2012-12-28 14:37 ` Andrew Lunn
2012-12-28 14:37 ` Andrew Lunn
2013-02-08 21:34 ` Grant Likely
2013-02-08 21:34 ` Grant Likely
2013-02-10 18:58 ` Andrew Lunn
2013-02-10 18:58 ` Andrew Lunn
2013-02-11 11:41 ` Grant Likely
2013-02-11 11:41 ` Grant Likely
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