Bug#608133: xserver-xorg-nouveau: displays nonsense on screen on Dell Dimension

[Ted Phelps <phelps@mantara.com>]

I'm seeing what I believe is the same issue on my NV40 card (built-in
graphics on an ASUS M2NPV-VM), and continue to see it even in
2.6.38-rc2.  I've git bisected and the issue started with kernel git
revision 72d7c3b: "x86: Use memblock to replace early_res" -- that's
when the GPU lockup first appeared.

After that patch, my dmesg output shows various memory ranges being
mapped to different locations:

  -kernel direct mapping tables up to bfef0000 @ 100000-704000
  +kernel direct mapping tables up to bfef0000 @ 1f9fc000-20000000
   ...
  -kernel direct mapping tables up to 130000000 @ 1a31000-23b7000
  +kernel direct mapping tables up to 130000000 @ bf56a000-bfef0000
   ...
  -  NODE_DATA [0000000100000000 - 0000000100004fff]
  - [ffffea0000000000-ffffea0004bfffff] PMD -> [ffff880100200000-ffff880103dfffff] on node 0
  +  NODE_DATA [000000012fffb000 - 000000012fffffff]
  + [ffffea0000000000-ffffea0004bfffff] PMD -> [ffff88012c200000-ffff88012fdfffff] on node 0
   ...
  -PCI-DMA: aperture base @ 20000000 size 65536 KB
  +PCI-DMA: aperture base @ b8000000 size 65536 KB

And this interesting message is no longer present:

  -early_res array is doubled to 64 at [16000 - 167ff]

And, finally, the following lines are new post-72d7c3b:

  +[drm] nouveau 0000:00:05.0: PFIFO_DMA_PUSHER - Ch 0
  +[drm] nouveau 0000:00:05.0: GPU lockup - switching to software fbcon

I haven't managed to work out if any of this means anything yet.  Any
guidance, even a suggestion of who to chase, would be greatly
appreciated.

Thanks,
-Ted