cpu_idle?

Zach Pfeffer zach.pfeffer at linaro.org
Wed Nov 30 19:56:42 UTC 2011


On 30 November 2011 11:41, Amit Kucheria <amit.kucheria at linaro.org> wrote:
> Wow - quite a cc-list :)
>
> On Tue, Nov 29, 2011 at 7:47 PM, Zach Pfeffer <zach.pfeffer at linaro.org> wrote:
>> Amit/Mounir,
>>
>> What's your guys plan with cpu_idle for each board? Are you going to
>> try and upstream a solution that will work across all boards? Would
>> you or Mounir be open to filing a BP per board so we can track when
>> cpu_idle will hit each board? Does it make sense to prototype
>> something across each board that we could land in Ubuntu and Android?
>>
>> Adding other people, leads, etc...
>
> I'll add four more.
>
> The people I've added to cc are the ones looking at upstreaming
> cpuidle for the various member platforms (the first 3 are Linaro
> assignees):
>
> Samsung - Amit Kachhap
> ST-E - Daniel Lezcano
> Freescale - Rob Lee
> TI - Kevin Hilman and Santosh Shilimkar
>
> Rob tried to upstream a driver for the imx5 platform. Russell
> suggested that it is time to have a common cpuidle stub driver for
> ARM[1].
>
> Daniel Lezcano and Rob are currently working on such a common stub
> driver. The imx5 cpuidle will get rebased on top of that. Daniel has
> actively started work on a u8500 cpuidle driver in the meanwhile but
> is awaiting documentation.
>
> For OMAP4, I was told that there was now a cpuidle driver on its way
> into mainline. But I didn't find one after a cursory glance at the
> lists. Perhaps Kevin/Santosh can shed some light there. The last known
> tree I was aware of for an OMAP4 cpuidle driver was TI maintained
> one[2].
>
> For exynos, there is a basic cpuidle driver in mainline. Amit Kachhap
> has been working on enhancing it[3] (adding more states and using more
> of the common code that was recently added).
>
> In summary, we should have cpuidle working on the member platforms in
> the coming month. If you want something today, you should look at
> enabling OMAP4 and Exynos cpuidle configs.
>
> Regards,
> Amit

Cool, thanks for the overview Amit.

Is there a test that a QA guy can run to verify that cpu_idle is
working? A set of commands and a proc node to cat out with some stats
perhaps?

> p.s Andy, was the breakage you reported in cpuidle related to the
> missing export.h patch?
>
> [1] http://thread.gmane.org/gmane.linux.ports.arm.kernel/132859/focus=133279
> [2] git://gitorious.org/omap-sw-develoment/linux-omap-dev.git
> for_3_2/omap4_mpuss_pm-integrated_2
> [3] http://thread.gmane.org/gmane.linux.kernel.samsung-soc/7877



-- 
Zach Pfeffer
Android Platform Team Lead, Linaro Platform Teams
Linaro.org | Open source software for ARM SoCs
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