Xorg failed to start on boot after upgrade using Nouveau and LightDM

[Bill Murnane]

Upgraded via update-manager from 11.10,
On restart got from tail /var/log/Xorg.0.log

 23.997] (II) NOUVEAU(0): NVEnterVT is called.
[ 24.661] (EE) NOUVEAU(0): failed to set mode: Invalid argument
Fatal server error:
[ 24.661] failed to create screen resources

The monitor briefly displayed 2 messages
[drm:drm_crtc_helper_set_config] *ERROR* failed to set mode on [CRTC:6]
then gave a text login prompt.

Tried renaming, and also copying /etc/X11/xorg.conf from xorg.conf.default still with same effect
Tried nomodeset but got a very slow, tiled, stripey desktop, unusable

Note: can run from liveCD 12.04 with no problem, tried this before upgrading

Note: have to run with option nolapic because of another bug #878031 .

excerpts from other logs
[drm] nouveau 0000:01:00.0: Detected an NV10 generation card (0x018100a2)

NV18 [GeForce4 MX 440 AGP 8x] (rev a2)
 Kernel driver in use: nouveau
 Kernel modules: nouveau, nvidiafb

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: xorg 1:7.6+12ubuntu1
ProcVersionSignature: Ubuntu 3.2.0-24.37-generic 3.2.14
Uname: Linux 3.2.0-24-generic i686
.tmp.unity.support.test.1:

ApportVersion: 2.0.1-0ubuntu7
Architecture: i386
CompizPlugins: [core,bailer,detection,composite,opengl,decor,mousepoll,blur,move,thumbnail,compiztoolbox,regex,place,imgpng,annotate,vpswitch,grid,gnomecompat,dbus,resize,splash,screenshot,animation,wall,session,wobbly,expo,workarounds,ezoom,staticswitcher,fade,scale,bench]
CompositorRunning: None
Date: Wed May 2 19:08:18 2012
DistUpgraded: 2012-04-29 00:45:55,281 DEBUG enabling apt cron job
DistroCodename: precise
DistroVariant: ubuntu
ExtraDebuggingInterest: Yes, whatever it takes to get this fixed in Ubuntu
GraphicsCard: NVIDIA Corporation NV18 [GeForce4 MX 440 AGP 8x] [10de:0181] (rev a2) (prog-if 00 [VGA controller])
InstallationMedia: Ubuntu 10.04 LTS "Lucid Lynx" - Release i386 (20100427.1)
ProcEnviron:
 TERM=xterm
 LANG=en_NZ.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-24-generic root=UUID=173b74ab-6232-45ed-861b-16fd44b7e4e0 ro ro nolapic quiet splash vt.handoff=7
SourcePackage: xorg
Symptom: display
Title: Xorg freeze
UpgradeStatus: Upgraded to precise on 2012-04-28 (3 days ago)
dmi.bios.date: 02/13/2005
dmi.bios.vendor: Intel Corp.
dmi.bios.version: RL86510A.86A.0089.P21.0502132202
dmi.board.name: D865PERL
dmi.board.vendor: Intel Corporation
dmi.board.version: AAC27648-210
dmi.chassis.type: 2
dmi.modalias: dmi:bvnIntelCorp.:bvrRL86510A.86A.0089.P21.0502132202:bd02/13/2005:svn:pn:pvr:rvnIntelCorporation:rnD865PERL:rvrAAC27648-210:cvn:ct2:cvr:
version.compiz: compiz 1:0.9.7.8-0ubuntu1
version.libdrm2: libdrm2 2.4.32-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 8.0.2-0ubuntu3
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental 8.0.2-0ubuntu3
version.libgl1-mesa-glx: libgl1-mesa-glx 8.0.2-0ubuntu3
version.xserver-xorg-core: xserver-xorg-core 2:1.11.4-0ubuntu10.1
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.7.0-0ubuntu1
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.99~git20111219.aacbd629-0ubuntu2
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.17.0-1ubuntu4
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20111201+b5534a1-1build2

[Bill Murnane (bill-murnane)]

after logging in in character mode startx was successful,

[Bill Murnane (bill-murnane)]

changed from lightdm to GDM window manager and logs in graphically. So maybe the problem is with lightdm

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.