Re: [Bug #12667] Badness at kernel/time/timekeeping.c:98 in pmud (timekeeping_suspended)

Thomas Gleixner
2009-02-22T19:31:59Z

On Fri, 20 Feb 2009, Benjamin Herrenschmidt wrote:
> On Thu, 2009-02-19 at 21:17 +0100, Thomas Gleixner wrote:
> >
> > Well, harsh or not is not the question here.
> >
> > Fact is that you call gettimeofday() _before_ the timekeeping code has
> > resumed.
> >
> > That's a simple ordering problem. timekeeping is in the sysdev class
> > as well and it's not the only sysdev which has explicit ordering
> > requirements.
>
> And how do I control that ordering ?
>
> I find that a bit fishy ... What about making gettimeofday() in the
> timekeeping code work, just return a frozen snapshot of the value on
> suspend instead ?

We had problems in the past where we just returned frozen time and the
calling code got surprised when the time jumped 5 hours ahead just a
few microseconds later.

What I find more fishy is the fact that the lid switch needs to be a
sysdev. It's a simple input event, which causes the user space code to
trigger the suspend sequence when the lid is shut.

Thanks,

tglx