linux-kernel - Re: [PATCH] ARM: timer: Shutdown clock event device when stopping local timer

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Message-ID: <20130330100408.GA17995@n2100.arm.linux.org.uk>
Date:	Sat, 30 Mar 2013 10:04:08 +0000
From:	Russell King - ARM Linux <linux@....linux.org.uk>
To:	Ning Jiang <ning.n.jiang@...il.com>
Cc:	Stephen Boyd <sboyd@...eaurora.org>, kgene.kim@...sung.com,
	davidb@...eaurora.org, dwalker@...o99.com, bryanh@...eaurora.org,
	john.stultz@...aro.org, tglx@...utronix.de,
	linus.walleij@...aro.org, shawn.guo@...aro.org,
	rob.herring@...xeda.com, arnd@...db.de,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-samsung-soc@...r.kernel.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH] ARM: timer: Shutdown clock event device when stopping
	local timer

On Sat, Mar 30, 2013 at 05:57:38PM +0800, Ning Jiang wrote:
> 2013/3/30 Stephen Boyd <sboyd@...eaurora.org>:
> > On 03/29/13 02:24, ning.n.jiang@...il.com wrote:
> >> From: Ning Jiang <ning.n.jiang@...il.com>
> >>
> >> Currently there are two problems when we try to stop local timer.
> >> First, it calls set_mode function directly so mode state is not
> >> updated for the clock event device. Second, it makes the device
> >> unused instead of shutdown.
> >
> > What device is this a problem on? I believe this only matters to drivers
> > which enable their timer in their set_next_event() callback? But even
> > then, does anything actually happen because the interrupt should have
> > been disabled in the local timer stop callback.
> >
> 
> Right. Drivers which enable timer in set_next_event() will have this problem.
> It will not have functional problem in my case. But my device cannot enter
> low power mode with a pending interrupt even if it is disabled.

You're not telling us what you have discovered.  How does set_next_event()
get called after we've set the mode to UNUSED in the current code?
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