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From: khilman@ti•com (Kevin Hilman)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v3 1/7] cpuidle: Add common init interface and idle functionality
Date: Tue, 24 Jan 2012 12:16:56 -0800	[thread overview]
Message-ID: <87hazkhn47.fsf@ti.com> (raw)
In-Reply-To: <1327379854-12403-2-git-send-email-rob.lee@linaro.org> (Robert Lee's message of "Mon, 23 Jan 2012 22:37:28 -0600")

Robert Lee <rob.lee@linaro•org> writes:

> The patch adds some cpuidle initialization functionality commonly
> duplicated by many platforms.
>
> Signed-off-by: Robert Lee <rob.lee@linaro•org>

[...]

> +static int simple_enter(struct cpuidle_device *dev,
> +			       struct cpuidle_driver *drv, int index)
> +{
> +	ktime_t time_start, time_end;
> +
> +	local_irq_disable();

Is this needed?   arch/arm/kernel/process.c:cpu_idle() already disables IRQs

> +	time_start = ktime_get();
> +
> +	index = do_idle[index](dev, drv, index);
> +
> +	time_end = ktime_get();
> +
> +	local_irq_enable();
> +
> +	dev->last_residency =
> +		(int)ktime_to_us(ktime_sub(time_end, time_start));

I don't think this cast is quite right here, since last_residency is an
int, it needs to be capped, or you'll end up with negative last_residency.

I think you need to do something like is done in poll_idle() in
drivers/cpuidle/cpuidle.c:

	diff = ktime_to_us(ktime_sub(t2, t1));
	if (diff > INT_MAX)
		diff = INT_MAX;


Speaking of poll_idle(), simple_idle() looks quite similar to it.   Maybe
they can be combined?

Kevin

  parent reply	other threads:[~2012-01-24 20:16 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-24  4:37 [PATCH v3 0/7] Add common cpuidle code for consolidation Robert Lee
2012-01-24  4:37 ` [PATCH v3 1/7] cpuidle: Add common init interface and idle functionality Robert Lee
2012-01-24 14:36   ` Rob Herring
2012-01-24 22:43     ` Rob Lee
2012-01-24 20:16   ` Kevin Hilman [this message]
2012-01-24 23:10     ` Rob Lee
2012-01-24 23:46   ` Turquette, Mike
2012-01-25  2:03     ` Rob Lee
2012-01-24 23:49   ` Daniel Lezcano
2012-01-25  2:38     ` Rob Lee
2012-01-25 14:52       ` Daniel Lezcano
2012-01-24  4:37 ` [PATCH v3 2/7] ARM: exynos: Modify to use new common cpuidle code Robert Lee
2012-01-29  4:47   ` Barry Song
2012-01-24  4:37 ` [PATCH v3 3/7] ARM: shmobile: " Robert Lee
2012-01-24  4:37 ` [PATCH v3 4/7] ARM: kirkwood: " Robert Lee
2012-01-24  4:37 ` [PATCH v3 5/7] ARM: davinci: " Robert Lee
2012-01-24  4:37 ` [PATCH v3 6/7] ARM: imx: Init imx5 gpc_dvfs clock for global use Robert Lee
2012-01-24  4:37 ` [PATCH v3 7/7] ARM: imx: Add imx5 cpuidle implementation Robert Lee
2012-01-24 20:08 ` [PATCH v3 0/7] Add common cpuidle code for consolidation Kevin Hilman
2012-01-24 20:17   ` Mark Brown
2012-01-25  0:41     ` Kevin Hilman
2012-01-25  0:46   ` Rob Lee
2012-01-25 18:58     ` Kevin Hilman
2012-01-29 15:34       ` Russell King - ARM Linux
2012-01-31  3:02         ` Rob Lee
2012-01-31 21:55           ` Kevin Hilman

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