Date: Sat, 14 May 2011 17:51:21 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Colin Cross <ccross@android.com>
cc: Linus Walleij <linus.walleij@linaro.org>,
        Santosh Shilimkar <santosh.shilimkar@ti.com>,
        Russell King <linux@arm.linux.org.uk>,
        Srinidhi KASAGAR <srinidhi.kasagar@stericsson.com>,
        Harald Gustafsson <harald.gustafsson@ericsson.com>,
        Linus Walleij <linus.ml.walleij@gmail.com>,
        linux-kernel@vger.kernel.org,
        Rickard ANDERSSON <rickard.andersson@stericsson.com>,
        martin persson <martin.persson@stericsson.com>,
        Varun Swara <Varun.Swara@arm.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] ARM: twd: Adjust localtimer frequency
 withcpufreqnotifiers
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On Fri, 13 May 2011, Colin Cross wrote:
> On Fri, May 13, 2011 at 3:02 AM, Thomas Gleixner <tglx@linutronix.de> wrote:
> > ?/**
> > + * clockevents_reconfigure - Reconfigure and reprogram a clock event device.
> > + * @dev: ? ? ? device to modify
> > + * @freq: ? ? ?new device frequency
> > + * @secr: ? ? ?guaranteed runtime conversion range in seconds
> > + *
> > + * Reconfigure and reprogram a clock event device in oneshot
> > + * mode. Must only be called from low level idle code where
> > + * interaction with hrtimers/nohz code etc. is not possible and
> > + * guaranteed not to conflict. Must be called with interrupts
> > + * disabled!
> > + * Returns 0 on success, -ETIME when the event is in the past or
> > + * -EINVAL when called with invalid parameters.
> > + */
> We need to call this from a cpufreq notifier with interrupts disabled,
> not from idle.

That works as well. Comments needs update. The important thing is that
neither a timer interrupt nor a hrtimer function should interfere on
that very cpu.

Thanks,

	tglx

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