On Wed, Sep 27, 2006 at 08:29:00AM -0500, Robert E. Blair wrote:
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> I don;t know if it is related, but I fought this battle with a much more
> recent kernel (ACPI issues made me do it) on a Core 2 Duo running
> x86_64.  The solution in my case was the "notsc" option at boot.  My
> fuzzy understanding of this is that in dual cores the two cpu clock
> registers are not always in sync and this causes odd timer behavior when
> flipping back and forth between cpu's.

Thanks for the tip. Unfortunately this didn't solve the problem in my
case. I'm still running only the single-processor kernel to allow at least
the desktop user to use X in a tolerable manner.

It may still be a timer problem though. Is it correct that I applied the
option like below (excerpt of the active kernel section in grub.conf)?

title Scientific Linux SL Release 3.0.4 (SL) (2.4.21-47.ELsmp)
     root (hd0,0)
     kernel /vmlinuz-2.4.21-47.ELsmp ro root=LABEL=/ hda=ide-scsi notsc
     initrd /initrd-2.4.21-47.ELsmp.img                           ^^^^^

I also saw notsc in conjunction with clock=pmtmr when searching the
internet for similar issues.

> 
> Christoph P. Kukulies wrote:
> > We are observing a strange effect here under X11 with a 2.4.21-47.EL kernel.
> > The keyboard repeats single keystrokes in a very unpleasant manner. 
> > I first thought that it was an issue that can be passed by by setting 
> > xset -r and then xset -r rate 400 30 but after short it turned out that
> > the problem did not go away with that. Motherboard is an ASUS A8N-E.
> > 

--
Chris Christoph P. U. Kukulies kukulies (at) rwth-aachen.de