Re: strange keyboard lag after suspend testing

From: Pavel Machek
Date: Tue Mar 20 2007 - 12:31:38 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:

root@amd:~# while true ; do echo -n . ; sleep .2; date; done
.Tue Mar 20 17:28:34 CET 2007
.Tue Mar 20 17:28:35 CET 2007
.Tue Mar 20 17:28:35 CET 2007
.Tue Mar 20 17:28:35 CET 2007
.Tue Mar 20 17:28:36 CET 2007
.Tue Mar 20 17:28:36 CET 2007
.Tue Mar 20 17:28:36 CET 2007
.Tue Mar 20 17:28:36 CET 2007
.Tue Mar 20 17:28:37 CET 2007
.Tue Mar 20 17:28:37 CET 2007
.Tue Mar 20 17:28:37 CET 2007
.Tue Mar 20 17:28:37 CET 2007
.Tue Mar 20 17:28:38 CET 2007
.Tue Mar 20 17:28:38 CET 2007
.Tue Mar 20 17:28:38 CET 2007
.Tue Mar 20 17:28:39 CET 2007
.Tue Mar 20 17:28:39 CET 2007
.Tue Mar 20 17:28:39 CET 2007
.Tue Mar 20 17:28:39 CET 2007
.Tue Mar 20 17:28:39 CET 2007
.Tue Mar 20 17:28:40 CET 2007
.Tue Mar 20 17:28:40 CET 2007
.Tue Mar 20 17:28:40 CET 2007
.Tue Mar 20 17:28:40 CET 2007
.Tue Mar 20 17:28:41 CET 2007
.Tue Mar 20 17:28:41 CET 2007
.Tue Mar 20 17:28:41 CET 2007
.Tue Mar 20 17:28:42 CET 2007
.Tue Mar 20 17:28:42 CET 2007

So sorry for false alarm, it is not keyboard related, it is just very
very strange.
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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