Executive summary 
~~~~~~~~~~~~~~~~~ 
Upon loading some Web pages in Konqueror, X becomes totally unresponsive (keypresses and mouse buttons aren't honored anymore; the mouse pointer still moves, though), forcing a reboot of the computer. While technically not a crash (the applications apparently continue to run) the end result is exactly the same.

Backtraces
~~~~~~~~~~
None, but see below for a Xorg log that might give some clues as to the origin of the problem.

How To Reproduce 
~~~~~~~~~~~~~~~~ 
  1. Fire up Konqueror
  2. Navigate to <http://www.legifrance.gouv.fr/WAspad/UnTexteDeJorf?numjo=DEVT0761717A>
  3. Konqueror displays the page, but the loading bar freezes at 25%
  4. Mouse clicks and keyboard events are now useless

Expected behaviour 
~~~~~~~~~~~~~~~~~~ 
The page should be loaded, and X11 should keep being usable after loading. This includes responding to user input.

Additional info 
~~~~~~~~~~~~~~~ 
  * OS was Debian Unstable, with kernel 2.6.21-2-k7
  * KDE version used was 3.5.7
  * Upon logging remotely onto the box, I noticed that the Xorg process was using ~90% CPU time
  * The log messages about out-of-order and tossed events (see below) continued to appear everytime I moved/clicked the mouse
  * I was not able to reproduce the bug with another browser; still, the above-mentioned messages seem Xorg-related, according to a Google search. Hence, I'm reporting the bug here. Feel free to advise if you think this is wrong

Xorg.0.log excerpt from the crashed session
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tossed event which came in late
mieqEnequeue: out-of-order valuator event; dropping.
tossed event which came in late
mieqEnequeue: out-of-order valuator event; dropping.
tossed event which came in late
mieqEnequeue: out-of-order valuator event; dropping.
tossed event which came in late
mieqEnequeue: out-of-order valuator event; dropping.
tossed event which came in late
mieqEnequeue: out-of-order valuator event; dropping.
tossed event which came in late
mieqEnequeue: out-of-order valuator event; dropping.
tossed event which came in late
mieqEnequeue: out-of-order valuator event; dropping.
tossed event which came in late
mieqEnequeue: out-of-order valuator event; dropping.
tossed event which came in late
mieqEnequeue: out-of-order valuator event; dropping.
tossed event which came in late
mieqEnequeue: out-of-order valuator event; dropping.
tossed event which came in late
mieqEnequeue: out-of-order valuator event; dropping.
tossed event which came in late
mieqEnequeue: out-of-order valuator event; dropping.
tossed event which came in late
mieqEnequeue: out-of-order valuator event; dropping.
tossed event which came in late
tossed event which came in late
tossed event which came in late
mieqEnequeue: out-of-order valuator event; dropping.
tossed event which came in late
mieqEnequeue: out-of-order valuator event; dropping.
tossed event which came in late
mieqEnequeue: out-of-order valuator event; dropping.
tossed event which came in late
tossed event which came in late

[due to Bugzilla length constraints, I'm not posting the entire Xorg log. If you need it, please tell me]

Complete xorg.conf file (minus leading comments)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Section "Extensions"
	Option		"Composite"		"Enable"
	Option		"RENDER"		"Enable"
EndSection

Section "InputDevice"
	Identifier	"Generic Keyboard"
	Driver		"kbd"
	Option		"CoreKeyboard"
	Option		"XkbRules"		"xorg"
	Option		"XkbModel"		"pc105"
	Option		"XkbLayout"		"fr"
	Option		"XkbVariant"		"latin9"
	Option		"XkbOptions"		"compose:menu"
EndSection

Section "InputDevice"
	Identifier	"Configured Mouse"
	Driver		"mouse"
	Option		"CorePointer"
	Option		"Device"		"/dev/input/mice"
	Option		"Protocol"		"ImPS/2"
EndSection

Section "Device"
	Identifier	"ATI Technologies Inc RV370 [Radeon X300SE]"
	Driver		"ati"
	BusID		"PCI:1:0:0"
#	Option		"AccelDFS"		"true"
	Option		"AccelMethod"		"EXA"
	Option		"AGPFastWrite"		"true"
	Option		"AGPMode"		"8"
	Option		"AGPSize"		"128"
	Option		"BufferSize"		"2"
	Option		"EnableDepthMoves"	"true"
	Option		"EnablePageFlip"	"true"
#	Option		"FBTexPercent"		"0"
	Option		"GARTSize"		"64"
#	Option		"IgnoreEDID"		"true"
	Option		"mtrr"			"true"
EndSection

Section "Monitor"
	Identifier	"NEC CI VR17"
	Option		"DPMS"
	HorizSync	30-70
	VertRefresh	50-150
EndSection

Section "Screen"
	Identifier	"Default Screen"
	Device		"ATI Technologies Inc RV370 [Radeon X300SE]"
	Monitor		"NEC CI VR17"
	DefaultDepth	24
	SubSection "Display"
		Modes	"1024x768" "800x600" "640x480"
	EndSubSection
EndSection

Section "ServerLayout"
	Identifier	"Default Layout"
	Screen		"Default Screen"
	InputDevice	"Generic Keyboard"
	InputDevice	"Configured Mouse"
EndSection

Section "DRI"
	Mode		0666
EndSection