Disabling DRI doesn't help. I copied Ubuntu's xorg.conf to RHEL4U2 and
it's X still works with no problem.
I will comment on Freedesktop.org's bugzilla.
Thanks!

On Tue, 2006-03-14 at 01:09 +0000, Paul Sladen wrote:
> Public bug report changed:
> https://launchpad.net/malone/bugs/34697
> 
> Comment:
> > It seems only RHEL 4 U2 has fixed it.
> 
> It could be that RHEL may have a more conservative configuration (eg. no
> DRI).  Are you able to copy across the config from the Ubuntu/SLES install
> and try that under RHEL?
> 
> Any differences between them may well show up a workaround/solution;  or
> otherwise we can start patch hunting.
> 
> BTW, could you report the fact that you think it's fixed in the RH release
> to the upstream FD.org bugzilla---that may give them clues too, and they're
> in a much better position to follow that up directly.


# /etc/X11/xorg.conf (xorg X Window System server configuration file)
#
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
#
# Edit this file with caution, and see the /etc/X11/xorg.conf manual page.
# (Type "man /etc/X11/xorg.conf" at the shell prompt.)
#
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# package.
#
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
#   sudo dpkg-reconfigure -phigh xserver-xorg

Section "Files"
	FontPath	"/usr/share/X11/fonts/misc"
	FontPath	"/usr/share/X11/fonts/cyrillic"
	FontPath	"/usr/share/X11/fonts/100dpi/:unscaled"
	FontPath	"/usr/share/X11/fonts/75dpi/:unscaled"
	FontPath	"/usr/share/X11/fonts/Type1"
	FontPath	"/usr/share/X11/fonts/100dpi"
	FontPath	"/usr/share/X11/fonts/75dpi"
	# path to defoma fonts
	FontPath	"/var/lib/defoma/x-ttcidfont-conf.d/dirs/TrueType"
EndSection

Section "Module"
	Load	"i2c"
	Load	"bitmap"
	Load	"ddc"
	Load	"dri"
	Load	"extmod"
	Load	"freetype"
	Load	"glx"
	Load	"int10"
	Load	"type1"
	Load	"vbe"
EndSection

Section "InputDevice"
	Identifier	"Generic Keyboard"
	Driver		"kbd"
	Option		"CoreKeyboard"
	Option		"XkbRules"	"xorg"
	Option		"XkbModel"	"pc104"
	Option		"XkbLayout"	"us"
EndSection

Section "InputDevice"
	Identifier	"Configured Mouse"
	Driver		"mouse"
	Option		"CorePointer"
	Option		"Device"		"/dev/input/mice"
	Option		"Protocol"		"ExplorerPS/2"
	Option		"Emulate3Buttons"	"true"
EndSection

Section "Device"
	Identifier	"Generic Video Card"
	Driver		"i810"
	BusID		"PCI:0:2:0"
EndSection

Section "Monitor"
	Identifier	"Generic Monitor"
	Option		"DPMS"
	HorizSync	28-64
	VertRefresh	43-60
EndSection

Section "Screen"
	Identifier	"Default Screen"
	Device		"Generic Video Card"
	Monitor		"Generic Monitor"
	DefaultDepth	24
	SubSection "Display"
		Depth		1
		Modes		"1280x1024"
	EndSubSection
	SubSection "Display"
		Depth		4
		Modes		"1280x1024"
	EndSubSection
	SubSection "Display"
		Depth		8
		Modes		"1280x1024"
	EndSubSection
	SubSection "Display"
		Depth		15
		Modes		"1280x1024"
	EndSubSection
	SubSection "Display"
		Depth		16
		Modes		"1280x1024"
	EndSubSection
	SubSection "Display"
		Depth		24
		Modes		"1280x1024"
	EndSubSection
EndSection

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

Section "DRI"
	Mode	0666
EndSection


# Xorg configuration created by system-config-display

Section "ServerLayout"
	Identifier     "single head configuration"
	Screen      0  "Screen0" 0 0
	InputDevice    "Mouse0" "CorePointer"
	InputDevice    "Keyboard0" "CoreKeyboard"
EndSection

Section "Files"

# RgbPath is the location of the RGB database.  Note, this is the name of the 
# file minus the extension (like ".txt" or ".db").  There is normally
# no need to change the default.
# Multiple FontPath entries are allowed (they are concatenated together)
# By default, Red Hat 6.0 and later now use a font server independent of
# the X server to render fonts.
	RgbPath      "/usr/X11R6/lib/X11/rgb"
	FontPath     "unix/:7100"
EndSection

Section "Module"
	Load  "dbe"
	Load  "extmod"
	Load  "fbdevhw"
	Load  "glx"
	Load  "record"
	Load  "freetype"
	Load  "type1"
	Load  "dri"
EndSection

Section "InputDevice"

# Specify which keyboard LEDs can be user-controlled (eg, with xset(1))
#	Option	"Xleds"		"1 2 3"
# To disable the XKEYBOARD extension, uncomment XkbDisable.
#	Option	"XkbDisable"
# To customise the XKB settings to suit your keyboard, modify the
# lines below (which are the defaults).  For example, for a non-U.S.
# keyboard, you will probably want to use:
#	Option	"XkbModel"	"pc102"
# If you have a US Microsoft Natural keyboard, you can use:
#	Option	"XkbModel"	"microsoft"
#
# Then to change the language, change the Layout setting.
# For example, a german layout can be obtained with:
#	Option	"XkbLayout"	"de"
# or:
#	Option	"XkbLayout"	"de"
#	Option	"XkbVariant"	"nodeadkeys"
#
# If you'd like to switch the positions of your capslock and
# control keys, use:
#	Option	"XkbOptions"	"ctrl:swapcaps"
# Or if you just want both to be control, use:
#	Option	"XkbOptions"	"ctrl:nocaps"
#
	Identifier  "Keyboard0"
	Driver      "kbd"
	Option	    "XkbModel" "pc105"
	Option	    "XkbLayout" "us"
EndSection

Section "InputDevice"
	Identifier  "Mouse0"
	Driver      "mouse"
	Option	    "Protocol" "IMPS/2"
	Option	    "Device" "/dev/input/mice"
	Option	    "ZAxisMapping" "4 5"
	Option	    "Emulate3Buttons" "yes"
EndSection

Section "Monitor"
	Identifier   "Monitor0"
	VendorName   "Monitor Vendor"
	ModelName    "Dell 1704FPT (Analog)"
	DisplaySize  340	270
	HorizSync    30.0 - 81.0
	VertRefresh  56.0 - 76.0
	Option	    "dpms"
EndSection

Section "Device"
	Identifier  "Videocard0"
	Driver      "i810"
	VendorName  "Videocard vendor"
	BoardName   "Intel 915"
EndSection

Section "Screen"
	Identifier "Screen0"
	Device     "Videocard0"
	Monitor    "Monitor0"
	DefaultDepth     24
	SubSection "Display"
		Viewport   0 0
		Depth     16
		Modes    "800x600" "640x480"
	EndSubSection
	SubSection "Display"
		Viewport   0 0
		Depth     24
		Modes    "1280x1024" "1280x960" "1152x864" "1024x768" "800x600" "640x480"
	EndSubSection
EndSection

Section "DRI"
	Group        0
	Mode         0666
EndSection