X windows related system hang

I have a Fedora Core 6 system that I just installed on an AIMB-330
motherboard (it's an SBC from Advantek).

It generally seems to work, except for irregular (but frequent) system
lockups when X windows starts. When the system locks there is some
junk at the top of the screen (and it looks like it's in video mode)
and the box stops responding to ping and all active SSH sessions go
dead.

Configuration notes:
I've tried several tweaks to the configuration. At the moment I'm
running with the attached xorg.conf file, which only loads the
'bitmap' module. This was done to eliminate the other modules as
possible sources of the problem.

The built in video on this board does support two monitors (FC6 is NOT
configured to support them). The driver is 'via' and the chipset is
reported as CLE266 (line 155 of attached log file). That jibes with

My test configuration is to bring the system up in runlevel 3 and run
startx as root with an empty ~/.Xclients file. This causes the X
server to start up and then shut down, so I can run startx repeatedly
and quickly.

I have also run the system with a 'reboot every 10 minutes' cron job
(booting into runlevel 5), and it will occasionally hang at startup in
the same manner. It's just quicker to get it to fail with the startx
trick.

The same sort of hang was present under FC1 on this system as well.

I've googled around a bit and can't quite make head nor tail out of this mess.

I've attached the Xorg.0.log file from the latest hang to this e-mail
(it looks pretty much the same as previous non-hang log files. Could
be that I didn't get a log in the hang case this time).

Any pointers to appropriate clues would be appreciated. This problem
has been troubling our systems for some time now, and I've finally
been assigned to hunt it down. I have the feeling that there is some
reasonable way to debug this, I just don't know what it is.

Thanks!

--
Michael Kohne
mhkohne@xxxxxxxxx

# Xorg configuration created by pyxf86config

Section "ServerLayout"
	Identifier     "Default Layout"
	Screen      0  "Screen0" 0 0
	InputDevice    "Keyboard0" "CoreKeyboard"
EndSection

Section "InputDevice"
	Identifier  "Keyboard0"
	Driver      "kbd"
	Option	    "XkbModel" "pc105"
	Option	    "XkbLayout" "us"
EndSection

Section "Device"
	Identifier  "Videocard0"
	Driver      "via"
EndSection

Section "Screen"
	Identifier "Screen0"
	Device     "Videocard0"
	DefaultDepth     24
	SubSection "Display"
		Viewport   0 0
		Depth     24
	EndSubSection
EndSection

#this section didn't exist before
Section "Module"
	Load "bitmap"
EndSection

Attachment: Xorg.0.log
Description: Binary data