* Pavel Machek <pavel@suse.cz> [050202 06:13]:
> 
> Hi!
> 
> > > > > I used your config advices from second mail, still it does not work as
> > > > > expected: system gets "too sleepy". Like it takes a nap during boot
> > > > > after "dyn-tick: Maximum ticks to skip limited to 1339", and key is
> > > > > needed to make it continue boot. Then cursor stops blinking and
> > > > > machine is hung at random intervals during use, key is enough to awake
> > > > > it.
> > > > 
> > > > Hmmm, that sounds like the local APIC does not wake up the PIT
> > > > interrupt properly after sleep. Hitting the keys causes the timer
> > > > interrupt to get called, and that explains why it keeps running. But
> > > > the timer ticks are not happening as they should for some reason.
> > > > This should not happen (tm)...
> > > 
> > > :-). Any ideas how to debug it? Previous version of patch seemed to work better...
> > 
> > I don't think it's HPET timer, or CONFIG_SMP. It also looks like your
> > local APIC timer is working.
> 
> I turned off CONFIG_PREEMPT, but nothing changed :-(.

What about reprogramming the timers in time.c after the sleep? Do
you to dyn_tick->skip = 1; part in dyn_tick_timer_interrupt?

It could also be that the reprogamming of PIT timer does not work on
your machine. I chopped off the udelays there... Can you try
something like this: