[PLUG] Two unusual problems: IRQ 15 running wild, Evolution/XFree86 crash on scroll?

["Michael F. Robbins" <mike@gamerack.com>]

I've been having two nasty problems for a while now.  Unfortunately,
that means that it's hard for me to track it down to a specific
upgrade/modification.  They may or may not be related.

First: Quake 3 Arena plays, but is jumpy.  About once a second (but it
doesn't seem to be regular) the game pauses temporarily.  People online
say that my player is jumpy, and I can certainly tell from my end. 
Running "glxgears" displays the same terrible behavior.  The same effect
is less visible when running other programs, but sometimes is noticable
(starting OpenOffice, for example).  This seems to coincide with my IRQ
15 going off the charts.
$ cat /proc/interrupts
           CPU0
  0:      51695          XT-PIC  timer
  1:       2388          XT-PIC  keyboard
  2:          0          XT-PIC  cascade
  4:        597          XT-PIC  serial
  5:          0          XT-PIC  usb-ohci
  7:    6958672          XT-PIC  parport0
  8:          4          XT-PIC  rtc
 10:       3152          XT-PIC  usb-ohci, eth0, ALi Audio Accelerator
 11:      35797          XT-PIC  nvidia
 12:      10462          XT-PIC  PS/2 Mouse
 14:       8455          XT-PIC  ide0
 15:    8880310          XT-PIC  ide1
NMI:          0
ERR:   15767809
And the IRQ 15 counter goes up by about 10,000 per second while I'm
running XFree86.  (I'm not so worried about the IRQ 7... the parallel
cable is disconnected and the IRQ line could be oscillating.) If XFree86
is not running, IRQ 15 appears to be normal.  Why would IRQ 15 be
running like this?

Second:
Scrolling down quickly in Evolution to the end of my inbox will
sometimes (maybe 1 of 5 times) crash X.  Evolution will freeze, XFree86
will freeze (at 100% CPU), and I have to use a serial terminal or SSH to
kill -9 the XFree86 process.  I can't find anything relavent in system
logs.  I tried connecting to a VNC session on my computer and was unable
to reproduce it that way.  Maybe it has something to do with fonts?  It
always crashes near the end of the list, where the message titles are
bold (new messages).  When it does crash, the screen is left only
partially redrawn.

Kernel 2.4.20
AMD Athlon on ECS K7AMA mobo
XFree86  4.2.1-6
Evolution 1.2.4-1

If I left out some critical information, please ask.

Michael F. Robbins
mike@gamerack.com

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