Re: strange keyboard lag after suspend testing

From: Pavel Machek
Date: Tue Mar 20 2007 - 12:38:55 EST


Hi!

> > >> > I was testing suspend in 2.6.21-rc4 a lot, and now... machine feels
> > >> > like someone added 50..100msec delay somewhere in keyboard
> > >> > handling. Mouse does not seem affected. /proc/interrupts seem to
> > >> > increase as they should, for both keyboard and mouse. Can someone
> > >> > reproduce it? Any ideas how to debug it?
> > >>
> > >> Probably just asking the obvious:
> > >> it's not a trivial "failed to re-configure repeat rate upon resume"
> > >> (which one could rule out by running "kbdrate" again)
> > >> but a lag in some interrupt handler or somewhere else deeper, right?
> > >
> > >No, it is not keyboard rate. Keyboard lags during normal typing,
> > >sometimes letters come in groups of two or so...
> >
> > I might start looking at embedded controller changes and switches. If
> > ACPI misbehaves that could starve keyboard controller... But you
> > said
>
> Mouse _seems_ okay, but I'm not sure if I'd notice lag there.
>
> > that mouse is OK... Hmm, what happens if you load evbug and type while
> > watching syslog. Do you observe the same delays?
>
> Hmm, seems that it only happens in X... so maybe it is some strange
> scheduling artefact?
>
> Hmm, something is wrong here:
>
> On console, I get expected 4-5 ticks a second. In x in gnome-terminal,
> I get this:

It gets weirder: I killed some tasks and now: (on unloaded system
running X, notice that top latency was ~1sec at 33:09).

root@amd:~# while true ; do echo -n . ; sleep .2; date; done
.Tue Mar 20 17:33:07 CET 2007
.Tue Mar 20 17:33:07 CET 2007
.Tue Mar 20 17:33:08 CET 2007
.Tue Mar 20 17:33:08 CET 2007
.Tue Mar 20 17:33:08 CET 2007
.Tue Mar 20 17:33:08 CET 2007
.Tue Mar 20 17:33:09 CET 2007
.Tue Mar 20 17:33:10 CET 2007
.Tue Mar 20 17:33:10 CET 2007
.Tue Mar 20 17:33:10 CET 2007
.Tue Mar 20 17:33:10 CET 2007
.Tue Mar 20 17:33:10 CET 2007
.Tue Mar 20 17:33:11 CET 2007
.Tue Mar 20 17:33:11 CET 2007
.Tue Mar 20 17:33:11 CET 2007
.Tue Mar 20 17:33:12 CET 2007
.Tue Mar 20 17:33:12 CET 2007

As soon as I load the cpu up with while1, machine starts to behave.

When I turn on bluetooth (USB), ACPI can no longer use C3, and machine
starts to behave. Hmm?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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