Re: RT throttling and suspend/resume (was Re: [PATCH] i2c: omap: revert "i2c: omap: switch to threaded IRQ support")

Peter Zijlstra
2012-10-19T14:00:27Z

On Thu, 2012-10-18 at 08:51 +0300, Felipe Balbi wrote:
> > So the primary question remains: is RT runtime supposed to include the
> > time spent suspended? I suspect not.
>
> you might be right there, though we need Thomas or Peter to answer :-s

re, sorry both tglx and I have been traveling, he still is, I'm trying
to play catch-up :-)

Anyway, yeah I'm somewhat surprised the clock is 'running' when the
machine isn't. From what I could gather, this is !x86 hardware, right?

x86 explicitly makes sure our clocks are 'stopped' during suspend, see
commit cd7240c0b900eb6d690ccee088a6c9b46dae815a.

Can you do something similar for ARM? A quick look at
arch/arm/kernel/sched_clock.c shows there's already suspend/resume
hooks, do they do the wrong thing?