Comment 0 for bug 139241

Bug reported by Zack Weinberg on the Debian BTS 2 weeks ago, discussed with airlied on IRC a couple times.

Since 6.6.192 and kernel 2.6.22, the radeon driver enables DRI on
  PCI:*(1:5:0) ATI Technologies Inc RC410 [Radeon Xpress 200M] rev 0
It results in a black screen for Zack.

The log with 6.6.193 and DRI is available at: http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=42;filename=xorg.log.6_6_193-1_dri;att=6;bug=437321
With DRI disabled in xorg.conf: http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=42;filename=xorg.log.6_6_193-1_no-dri;att=5;bug=437321

With AIGLX disabled (requested by airlied):
http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=52;filename=xorg.log.6_6_193-1_no-aiglx;att=1;bug=437321

And finally, airlied requested the dmesg output when debug is enabled in the drm kernel module:
http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=62;bug=437321

I am marking as a blocker for 6.7 in case it's easy to fix. But, this "regression" may be easily worked around by disabling DRI, feel free to unblock if there's too much work needed to fix this...