Re: [PATCH] clocksource: timer-atmel-pit: don't suspend/resume if unused

[Daniel Lezcano]

On 01/15/2015 12:52 PM, Alexandre Belloni wrote:
> Hi,
>
> I'll do it but only if you review my other series :)

deal ! ;)

  -- Daniel


> On 15/01/2015 at 12:41:27 +0100, Daniel Lezcano wrote :
> > On 01/13/2015 11:47 AM, Thomas Gleixner wrote:
> > > On Mon, 12 Jan 2015, Daniel Lezcano wrote:
> > >
> > > > On 01/12/2015 03:04 PM, Nicolas Ferre wrote:
> > > > > Le 18/12/2014 15:05, Nicolas Ferre a Ãcrit :
> > > > > > From: Sylvain Rochet <sylvain.rochet@xxxxxxxxxxxx>
> > > > > >
> > > > > > Waiting for PIT to stop counting takes a long time:
> > > > > >     1/(Master clock/prescaler/PIVR)
> > > > > > = 1/(133 MHz     /16       /2^20)
> > > > > > = 126 ms
> > > > > >
> > > > > > Up to 126 ms if master clock is set to 133 MHz, skipping suspend/resume
> > > > > > of the unused PIT device reduce (suspend time + resume time) from ~140 ms
> > > > > > to ~17 ms.
> > > > > >
> > > > > > Signed-off-by: Sylvain Rochet <sylvain.rochet@xxxxxxxxxxxx>
> > > > > > [nicolas.ferre@xxxxxxxxx: move to newer clocksource driver]
> > > > > > Signed-off-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>
> > > > > > Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
> > > > > > ---
> > > > > > Hi Sylvain,
> > > > > >
> > > > > > I re-worked (and "Acked") your patch so it can be applied on the newer
> > > > > > Mainline
> > > > > > kernels. Beware, I changed the "subject line" as well. The PIT driver
> > > > > > moved
> > > > > > recently (3.18).
> > > > > >
> > > > > > Daniel,
> > > > > > Can you take this patch in your tree?
> > > > >
> > > > > Hi Daniel,
> > > > >
> > > > > Anything prevents this patch from being merged (aka ping ;-))?
> > > >
> > > > [Cc'ed tglx].
> > > >
> > > > Hi Nico,
> > > >
> > > > thanks for the head up.
> > > >
> > > > Nothing prevents it but I am wondering if this change shouldn't be in the
> > > > generic framework (kernel/time/clocksource.c and kernel/time/clockevents.c),
> > > > so all drivers will benefit this change ?
> > >
> > > Indeed. There is no point in calling suspend/resume for unused
> > > clockevents. They should be stopped and disabled already.
> >
> > Hi Nico,
> >
> > are you planning to do the change in the generic framework ?
> >
> > Thanks
> >    -- Daniel
> >
> > > Now with clocksources this might be different. We have no explicit
> > > state for this, but its trivial to add one at least for those
> > > clocksources which have enable/disable callbacks. For the other ones
> > > not so much.
> >
> >
> >
> >
> >
> > --
> >   <http://www.linaro.org/> Linaro.org â Open source software for ARM SoCs
> >
> > Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
> > <http://twitter.com/#!/linaroorg> Twitter |
> > <http://www.linaro.org/linaro-blog/> Blog


--
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