Lockup on X server start with Radeon on X.org 6.9

[Kevin Shanahan]

Hi,

I was just wondering if someone might be able to guide me as to what
to do to track down and hopfully fix a few regressions that I've come
across when upgrading my Debian system from xorg 6.8.2 to 6.9. I've
filed a bug report in Debian's BTS with all the details:

  http://bugs.debian.org/345729

I could file a bug in the fdo bugzilla also if you think that would be
useful.

Quick summary:
  - Hardware is a Radeon Mobility M6 LY, x86
  - Had no problems with xorg 6.8.2, only since upgrade to 6.9 (Debian)
  - Starting X with Load "dri" in the module section almost always hard
    locks the system (say 95% of the time).
  - If I manage to get in that 5% that works, the server is perfectly
    stable to use, including GL apps (GLQuake is what I'm mostly using).
  - Without the dri module loaded, the server starts most of the time
    (say 95%), but it does seem to occasionally lock up as well. It's
    possible that these cases might have been due to incomplete reset of
    the video card after a previous lockup with dri, but I did always
    power off the laptop between boots, since alt-sysrq-b doesn't work
    with these lockups.
  - VT switching away from the x-server seems okay, but switching back
    again usually locks up the machine.

Since then I've also tried testing with combinations of the following
options on or off in my device section, with no apparent change:

       Option      "DynamicClocks" "off"
       Option      "RenderAccel" "off"
       Option      "AccelMethod" "exa"

Thanks for any advice.

Regards,
Kevin.