In the last week or so, my X has started to freeze from time to time.
This tends to happen when I switch focus between windows. Switching to
either Mozilla or Opera has caused this, but the same thing has happened
while I've been running xpat2 (solitaire card game) or just sitting
there doing nothing. At other times, I can leave the computer running
around the clock for a few days without a problem.

When this happens, neither mouse movements nor keypresses have an
effect. I can't change focus or bring up the menu to restart/kill X, and
I can't Ctrl-Alt-Backspace to get back to the command line. My desktop
clock (wmClock) also stops moving, so I figure that this is more than
just a problem with the input devices. Rebooting via the reset button
gets everything running normally.

I'm using Debian Woody, but different libraries and programs have been
updated. The kernel is 2.6.9, X is version I installed the new
libc6 recently, version 2.3.2, along with the different libraries that
version requires. That upgrade was around the same time that the
freezing started, although this could just be a coincidence.

Nothing in syslog or the XFree86.0.log jumps out to me as being related
to these freezes. Everything looks normal, until suddenly the log starts
referring to what happened after the reboot. I'm unaware of any other
log files that might be useful.

So, the question: does anyone have any thoughts on what could be causing
this? I haven't been able to find this problem in google searches or
reading through various newsgroups.

Thanks in advance for any help,