DRI not working with ATI Radeon M7

[Fabrice Medio <fab@rhapsodyk.net>]

Hello !

I have an very recent iBook2 here, with the following installed : 
- 2.4.20 + latest benh kernel patches ;
- latest drm-trunk modules ;
- latest xserver from drm trunk.

/proc/pci says the video card is :
  Bus  0, device  16, function  0:
    VGA compatible controller: ATI Technologies Inc Radeon Mobility M7 LW (rev 0).

My XF86Config-4 states the following (amongst other stuff) :

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

Section "Device"
	Identifier	"TiBook Internal Video"
	Driver		"radeon"
	Option		"UseFBDev"
	Option		"DRIReinit"
EndSection

Section "DRI"
	Group	"dri"
	Mode	0666
EndSection

When X is launched, the screen just stays blank (i.e, black). When I
ssh the iBook from another machine, 'top' says X takes 99.9% of CPU
cycles. Killing -9 the 'X' process halts it, but the screen doesn't
return to console state, and remains black instead. 

Now, when I use the regular 'radeon' kernel module shipped within the
last benh kernel, X works normally, but without DRI.

Any suggestion to get DRI to work properly would be greatly
appreciated.

Thanks in advance

Fabrice