Comment 4 for bug 1018015

Last night's update fixed it. Still no idea what it was, but here's the list of packages that have been updated. The usual suspects are:

compiz:amd64 (0.9.7.8-0ubuntu1.2, 0.9.7.8-0ubuntu1.3)
compiz-core:amd64 (0.9.7.8-0ubuntu1.2, 0.9.7.8-0ubuntu1.3)
compiz-gnome:amd64 (0.9.7.8-0ubuntu1.2, 0.9.7.8-0ubuntu1.3)
compiz-plugins:amd64 (0.9.7.8-0ubuntu1.2, 0.9.7.8-0ubuntu1.3)
compiz-plugins-default:amd64 (0.9.7.8-0ubuntu1.2, 0.9.7.8-0ubuntu1.3)
nvidia-current-updates:amd64 (295.49-0ubuntu0.1, 295.49-0ubuntu0.2)
xserver-common:amd64 (1.11.4-0ubuntu10.6, 1.11.4-0ubuntu10.7)
xserver-xorg-core:amd64 (1.11.4-0ubuntu10.6, 1.11.4-0ubuntu10.7)

Don't know which one did it; other things on the list don't seem to be even remotely relevant. Pm-utils is not among them. I tried various versions of nvidia, including the one that was known to work before. The current kernel is 3.2.0-29-generic #46-Ubuntu SMP.

Start-Date: 2012-08-06 22:53:39

accountsservice:amd64 (0.6.15-2ubuntu9.2, 0.6.15-2ubuntu9.3)
base-files:amd64 (6.5ubuntu6, 6.5ubuntu6.2)
compiz:amd64 (0.9.7.8-0ubuntu1.2, 0.9.7.8-0ubuntu1.3)
compiz-core:amd64 (0.9.7.8-0ubuntu1.2, 0.9.7.8-0ubuntu1.3)
compiz-gnome:amd64 (0.9.7.8-0ubuntu1.2, 0.9.7.8-0ubuntu1.3)
compiz-plugins:amd64 (0.9.7.8-0ubuntu1.2, 0.9.7.8-0ubuntu1.3)
compiz-plugins-default:amd64 (0.9.7.8-0ubuntu1.2, 0.9.7.8-0ubuntu1.3)
cups:amd64 (1.5.3-0ubuntu2, 1.5.3-0ubuntu3)
cups-bsd:amd64 (1.5.3-0ubuntu2, 1.5.3-0ubuntu3)
cups-client:amd64 (1.5.3-0ubuntu2, 1.5.3-0ubuntu3)
cups-common:amd64 (1.5.3-0ubuntu2, 1.5.3-0ubuntu3)
cups-ppdc:amd64 (1.5.3-0ubuntu2, 1.5.3-0ubuntu3)
End-Date: 2012-08-06 23:07:45
firefox:amd64 (14.0.1+build1-0ubuntu0.12.04.1, 14.0.1+build1-0ubuntu0.12.04.2)
firefox-globalmenu:amd64 (14.0.1+build1-0ubuntu0.12.04.1, 14.0.1+build1-0ubuntu0.12.04.2)
firefox-gnome-support:amd64 (14.0.1+build1-0ubuntu0.12.04.1, 14.0.1+build1-0ubuntu0.12.04.2)
firefox-locale-en:amd64 (14.0.1+build1-0ubuntu0.12.04.1, 14.0.1+build1-0ubuntu0.12.04.2)
gcalctool:amd64 (6.4.1.1-0ubuntu2, 6.4.1.1-0ubuntu3)
gir1.2-accountsservice-1.0:amd64 (0.6.15-2ubuntu9.2, 0.6.15-2ubuntu9.3)
google-chrome-beta:amd64 (21.0.1180.57-r148591, 21.0.1180.64-r150042)
isc-dhcp-client:amd64 (4.1.ESV-R4-0ubuntu5.2, 4.1.ESV-R4-0ubuntu5.3)
isc-dhcp-common:amd64 (4.1.ESV-R4-0ubuntu5.2, 4.1.ESV-R4-0ubuntu5.3)
language-pack-en:amd64 (12.04+20120618, 12.04+20120801)
language-pack-en-base:amd64 (12.04+20120508, 12.04+20120801)
language-pack-gnome-en:amd64 (12.04+20120618, 12.04+20120801)
language-pack-kde-en:amd64 (12.04+20120618, 12.04+20120801)
language-pack-kde-en-base:amd64 (12.04+20120508, 12.04+20120801)
libaccountsservice0:amd64 (0.6.15-2ubuntu9.2, 0.6.15-2ubuntu9.3)
libbonobo2-0:amd64 (2.32.1-0ubuntu1, 2.32.1-0ubuntu1.1)
libbonobo2-common:amd64 (2.32.1-0ubuntu1, 2.32.1-0ubuntu1.1)
libbonoboui2-0:amd64 (2.24.5-0ubuntu1, 2.24.5-0ubuntu1.1)
libbonoboui2-common:amd64 (2.24.5-0ubuntu1, 2.24.5-0ubuntu1.1)
libcups2:amd64 (1.5.3-0ubuntu2, 1.5.3-0ubuntu3)
libcups2-dev:amd64 (1.5.3-0ubuntu2, 1.5.3-0ubuntu3)
libcups2:i386 (1.5.3-0ubuntu2, 1.5.3-0ubuntu3)
libcupscgi1:amd64 (1.5.3-0ubuntu2, 1.5.3-0ubuntu3)
libcupsdriver1:amd64 (1.5.3-0ubuntu2, 1.5.3-0ubuntu3)
libcupsimage2:amd64 (1.5.3-0ubuntu2, 1.5.3-0ubuntu3)
libcupsimage2:i386 (1.5.3-0ubuntu2, 1.5.3-0ubuntu3)
libcupsmime1:amd64 (1.5.3-0ubuntu2, 1.5.3-0ubuntu3)
libcupsppdc1:amd64 (1.5.3-0ubuntu2, 1.5.3-0ubuntu3)
libdecoration0:amd64 (0.9.7.8-0ubuntu1.2, 0.9.7.8-0ubuntu1.3)
libnux-2.0-0:amd64 (2.12.0-0ubuntu1, 2.14.0-0ubuntu1)
libnux-2.0-common:amd64 (2.12.0-0ubuntu1, 2.14.0-0ubuntu1)
libparted0debian1:amd64 (2.3-8ubuntu5, 2.3-8ubuntu5.1)
libpython2.7:amd64 (2.7.3-0ubuntu3, 2.7.3-0ubuntu3.1)
nux-tools:amd64 (2.12.0-0ubuntu1, 2.14.0-0ubuntu1)
nvidia-current-updates:amd64 (295.49-0ubuntu0.1, 295.49-0ubuntu0.2)
parted:amd64 (2.3-8ubuntu5, 2.3-8ubuntu5.1)
python2.7:amd64 (2.7.3-0ubuntu3, 2.7.3-0ubuntu3.1)
python2.7-dev:amd64 (2.7.3-0ubuntu3, 2.7.3-0ubuntu3.1)
python2.7-minimal:amd64 (2.7.3-0ubuntu3, 2.7.3-0ubuntu3.1)
remmina:amd64 (1.0.0-1ubuntu6.1, 1.0.0-1ubuntu6.2)
remmina-common:amd64 (1.0.0-1ubuntu6.1, 1.0.0-1ubuntu6.2)
remmina-plugin-rdp:amd64 (1.0.0-1ubuntu6.1, 1.0.0-1ubuntu6.2)
remmina-plugin-vnc:amd64 (1.0.0-1ubuntu6.1, 1.0.0-1ubuntu6.2)
software-center:amd64 (5.2.4, 5.2.5)
ubuntu-docs:amd64 (12.04.5, 12.04.6)
unity-greeter:amd64 (0.2.8-0ubuntu1.1, 0.2.8-0ubuntu1.2)
update-manager:amd64 (0.156.14.6, 0.156.14.7)
update-manager-core:amd64 (0.156.14.6, 0.156.14.7)
Upgrade: language-pack-gnome-en-base:amd64 (12.04+20120508, 12.04+20120801)
usb-creator-common:amd64 (0.2.38, 0.2.38.1)
usb-creator-gtk:amd64 (0.2.38, 0.2.38.1)
xserver-common:amd64 (1.11.4-0ubuntu10.6, 1.11.4-0ubuntu10.7)
xserver-xorg-core:amd64 (1.11.4-0ubuntu10.6, 1.11.4-0ubuntu10.7)
xserver-xorg-dev:amd64 (1.11.4-0ubuntu10.6, 1.11.4-0ubuntu10.7)

I haven't kept the logs from before June 23, which is approximately when I noticed the problem. But here is another hint at nvidia, although it could be something else installed earlier:

Start-Date: 2012-06-23 21:54:41
Install: nvidia-current:amd64 (302.17-0ubuntu1~precise~xup1)
nvidia-settings:amd64 (302.17-0ubuntu1~precise~xup3, automatic)