Re: TSC not updating after resume: Bug or Feature?

From: Deepak Saxena
Date: Tue Dec 23 2008 - 17:04:13 EST


On Sun, Dec 21, 2008 at 10:19:12PM +0100, Thomas Gleixner wrote:
> > of cycles (~2000 ftrace entries). From following the ftrace, what is
> > happening is that the clocksource is not updated until we run the cpu_idle()
> > thread due to an explicit scheduling operation in the resume path that occurs
> > via call to msleep from pci_set_power_state(). As I'm still fully groking the
> > timekeeping code, the question(s) I have is whether this is expected behaviour
> > and I should not assume valid timestamp data in the initial bits of the suspend path,
> > whether this is an OLPC-specific bug, or whether I've uncovered a generic bug in
> > the timekeeping implementation. This is on 2.6.27.7 as I've not gotten 28-rc
> > up and running on the XO but can move that up in priority if this behaviour
> > is different in newer kernels.
>
> Can you please upload the full trace somewhere ?
>
> Thanks,

Thomas,

Sorry for the delayed response...travelling and have very limited
connectivity. I will read the thread in detail when back online in a
few days.

http://dev.laptop.org/~dsaxena/suspend-trace-1267

~Deepak

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