Comment 11 for bug 341363

You may be right.

root@jaunty# grep 'upgrade libdrm' /var/log/dpkg.log
2009-03-10 17:22:09 upgrade libdrm2 2.4.4-0ubuntu6 2.4.5-0ubuntu1
2009-03-10 17:22:10 upgrade libdrm-intel1 2.4.4-0ubuntu6 2.4.5-0ubuntu1

So I downgraded to previous versions of packages:

libdrm2:
  Installed: 2.4.4-0ubuntu6
  Candidate: 2.4.5-0ubuntu1
libdrm-intel1:
  Installed: 2.4.4-0ubuntu6
  Candidate: 2.4.5-0ubuntu1
xserver-xorg-video-intel:
  Installed: 2:2.6.1-1ubuntu4
  Candidate: 2:2.6.3-0ubuntu1

Result:
 - I don't find any error during boot
 - I don't find any error when locking the screen (xflock4)
 - But I still have an error when I switch to another VT (even if it works OK)

root@jaunty# grep '\((EE\|WW)\)' /var/log/Xorg.0.log
[ 0.041547] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist.
[ 0.751200] (WW) intel(0): libpciaccess reported 0 rom size, guessing 64kB
[ 1.947025] (WW) intel(0): Register 0x61200 (PP_STATUS) changed from 0xc0000008 to 0xd000000a
[ 1.947064] (WW) intel(0): PP_STATUS before: on, ready, sequencing idle
[ 1.947085] (WW) intel(0): PP_STATUS after: on, ready, sequencing on
[ 2.003938] (WW) intel(0): DRI2 requires UXA
[ 2.119477] (EE) intel(0): Non-contiguous GTT entries: (6295552,0x163ffbe000) vs (6291456,0x3fe00000)
[ 2.119550] (EE) intel(0): Non-contiguous GTT entries: (6299648,0x163fe02000) vs (6295552,0x3ffbe000)
[ 2.119656] (WW) intel(0): xf86AllocateGARTMemory: allocation of 10 pages failed
[ 2.119704] (EE) intel(0): Non-contiguous GTT entries: (6295552,0x163ffbe000) vs (6291456,0x3fe00000)
[ 2.119761] (EE) intel(0): Non-contiguous GTT entries: (6299648,0x163fe02000) vs (6295552,0x3ffbe000)
[ 2.119828] (EE) intel(0): Non-contiguous GTT entries: (6295552,0x163ffbe000) vs (6291456,0x3fe00000)
[ 2.119887] (EE) intel(0): Non-contiguous GTT entries: (6299648,0x163fe02000) vs (6295552,0x3ffbe000)
[ 172.953133] (WW) intel(0): ESR is 0x00000001, instruction error
[ 172.953185] (WW) intel(0): Existing errors found in hardware state.

root@jaunty# dmesg |grep drm
[ 27.658539] [drm] Initialized drm 1.1.0 20060810
[ 27.686730] [drm] Initialized i915 1.6.0 20080730 on minor 0
[ 194.048507] [drm:i915_get_vblank_counter] *ERROR* trying to get vblank count for disabled pipe 0