Radeon XPRESS 200M (RC410) - system lockup on DRI with 2.6.32-rc3 and Fedora 10 userspace

[Alex Villací­s Lasso]

http://bugzilla.kernel.org/show_bug.cgi?id=14331

I am testing kernel releases on a machine with the following radeon 
chipset as reported by lspci -v:

01:05.0 VGA compatible controller: ATI Technologies Inc RC410 [Radeon 
Xpress 200] (prog-if 00 [VGA controller])
    Subsystem: Intel Corporation Device d600
    Flags: bus master, 66MHz, medium devsel, latency 64, IRQ 17
    Memory at d8000000 (32-bit, prefetchable) [size=128M]
    I/O ports at ee00 [size=256]
    Memory at fdef0000 (32-bit, non-prefetchable) [size=64K]
    [virtual] Expansion ROM at fde00000 [disabled] [size=128K]
    Capabilities: [50] Power Management version 2
    Capabilities: [80] Message Signalled Interrupts: Mask- 64bit- 
Count=1/1 Enable-
    Kernel modules: radeon

On all of these tests, I use the Fedora 10 distro with kernel 
modesetting disabled and with the latest updates:

xorg-x11-server-common-1.5.3-17.fc10.i386
xorg-x11-server-Xorg-1.5.3-17.fc10.i386
xorg-x11-drv-ati-6.10.0-2.fc10.i386
mesa-dri-drivers-7.2-0.15.fc10.i386
mesa-libOSMesa-7.2-0.15.fc10.i386
mesa-libGL-7.2-0.15.fc10.i386
libdrm-2.4.0-0.21.fc10.i386

I know these versions do not follow the latest developments from xorg, 
but up to vanilla kernel 2.6.31.1, I had somewhat decent DRI and Compiz 
support. So I expected that the changes to radeon kernel support would 
continue to work with the old userspace. However, with 2.6.32-rc3 (and 
now 2.6.32-rc2), I get a system lockup with a black screen and an 
unresponsive keyboard when X starts up. The keyboard leds do not blink, 
so this makes me think that the kernel is caught in a loop instead of 
having a kernel panic. Opened ssh sessions into the machine also become 
unresponsive. When checking the xorg logs, the log stops at the line 
"drmOpenDevice: node name is /dev/dri/card0".

Adding Option "DRI" "off" to xorg.conf allows me to start up X, but I 
lose DRI and compiz.

I would like your opinion about the following issues:
* Should I expect DRI to continue working for radeon in a setup with a 
newer kernel and old userspace?
* Have any of you experienced anything similar with 2.6.32-rc2 onwards?

-- 
perl -e '$x=2.3;printf("%.0f + %.0f = %.0f\n",$x,$x,$x+$x);'