Re: next-20120313 cpuidle freezes when booting

From: Hugh Dickins
Date: Wed Mar 14 2012 - 16:31:30 EST


On Wed, 14 Mar 2012, Daniel Lezcano wrote:
> On 03/14/2012 08:03 PM, Hugh Dickins wrote:
> > On Wed, 14 Mar 2012, Daniel Lezcano wrote:
> > > On 03/13/2012 11:29 PM, Hugh Dickins wrote:
> > > >
> > > > Yesterday's 3.3.0-rc7-next-20120313 gives me unpredictable freezes
> > > > on x86_64, on a ThinkPad T420s - I've not dared it on more machines.
> > >
> > > is it possible you give the cpuidle driver your host is using ?
> >
> > "grep IDLE .config" tells me:
> >
> > CONFIG_ARCH_HAS_CPU_IDLE_WAIT=y
> > CONFIG_ARCH_HAS_DEFAULT_IDLE=y
> > CONFIG_CPU_IDLE=y
> > CONFIG_CPU_IDLE_GOV_LADDER=y
> > CONFIG_CPU_IDLE_GOV_MENU=y
> > CONFIG_INTEL_IDLE=y
> > # CONFIG_I7300_IDLE is not set
> >
> > but I've a feeling that isn't what you need to know.
>
> Thanks for these informations, I forgot to ask you for them.
> By the way, do you have CONFIG_ARCH_HAS_CPU_RELAX ?

Yes.

>
> > Is there some /proc or /sys file I can read to tell you?
>
> Yes, the content of /sys/devices/system/cpu/cpuidle/current_driver

intel_idle

> and /sys/devices/system/cpu/cpuidle/current_governor_ro

menu

>
> > Though if it's something that changes dynamically, then what
> > I read now might not be what it would say when things go wrong.
>
> No, that won't change, so the information should be enough for me to find the
> code path where the regression is.
>
> > I expect you've realized by now, I haven't a clue about cpuidle
> > drivers: I hadn't even realized that idleness needs a driver.
>
> No problem, thanks for git bisecting and find the culprit :)

Thank you - let me know if you've something you'd like me to try.

Hugh
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