DRI deadlock on dual head setup

[Antithesis]

Hi,

I'm running into a lot of issues trying to setup my dual monitors, following an update to Ubuntu Hardy. I've had dual monitors working before on this machine (ATI X300, Asus A8V-E board). I keep running into an issue where with a working fglrx driver, switching from clone mode to dual head leads to a DRI deadlock race between fglrx(0) and fglrx(1).
As a result, any related command (fglrxinfo, glxgears, amdcccle, gnome screensaver) will hang.

I've tried removing the ubuntu drivers and installing from the latest (8.476), and still get the same problem.

Below is my xorg.conf (which I've tried fiddling with to no avail - this is a clean copy using aticonfig --initial=dual-head).
Here is Xorg.0.log (truncated, as the errors never stop, long after login) - http://pastebin.ca/1017994

Section "ServerLayout"
	Identifier     "Default Layout"
	Screen      0  "aticonfig-Screen[0]" 0 0
	Screen         "aticonfig-Screen[1]" RightOf "aticonfig-Screen[0]"
EndSection

Section "Files"
EndSection

Section "Module"
EndSection

Section "InputDevice"
	Identifier  "Generic Keyboard"
	Driver      "kbd"
	Option	    "XkbRules" "xorg"
	Option	    "XkbModel" "pc105"
	Option	    "XkbLayout" "us"
	Option	    "XkbVariant" "he"
EndSection

Section "InputDevice"
	Identifier  "Configured Mouse"
	Driver      "mouse"
	Option	    "CorePointer"
EndSection

Section "Monitor"
	Identifier   "aticonfig-Monitor[0]"
	Option	    "VendorName" "ATI Proprietary Driver"
	Option	    "ModelName" "Generic Autodetecting Monitor"
	Option	    "DPMS" "true"
EndSection

Section "Monitor"
	Identifier   "aticonfig-Monitor[1]"
	Option	    "VendorName" "ATI Proprietary Driver"
	Option	    "ModelName" "Generic Autodetecting Monitor"
	Option	    "DPMS" "true"
EndSection

Section "Device"
	Identifier  "aticonfig-Device[0]"
	Driver      "fglrx"
	BusID       "PCI:2:0:0"
EndSection

Section "Device"
	Identifier  "aticonfig-Device[1]"
	Driver      "fglrx"
	BusID       "PCI:2:0:0"
	Screen      1
EndSection

Section "Screen"
	Identifier "aticonfig-Screen[0]"
	Device     "aticonfig-Device[0]"
	Monitor    "aticonfig-Monitor[0]"
	DefaultDepth     24
	SubSection "Display"
		Viewport   0 0
		Depth     24
	EndSubSection
EndSection

Section "Screen"
	Identifier "aticonfig-Screen[1]"
	Device     "aticonfig-Device[1]"
	Monitor    "aticonfig-Monitor[1]"
	DefaultDepth     24
	SubSection "Display"
		Viewport   0 0
		Depth     24
	EndSubSection
EndSection