Forwarding this bug from Ubuntu reporter Stephen Rees-Carter:
On a fresh install of 12.04, on my Thinkpad L520 with sandybridge graphics, the primary monitor displays nothing. An external monitor connected will work fine. This setup works fine in previous versions of Ubuntu. (Previous versions need the 'noapic' flag to boot though).
Someone else reported similar problems on a Thinkpad L520, and also saw it on Ubuntu 11.10 with the vanilla 3.2.0 kernel compiled from kernel.org source. They worked around it by disabling modesetting in grub.
[ 22.840] (II) intel(0): Output LVDS1 connected
[ 22.840] (II) intel(0): Output VGA1 connected
[ 22.840] (II) intel(0): Output HDMI1 disconnected
[ 22.840] (II) intel(0): Output DP1 disconnected
[ 22.840] (II) intel(0): Output HDMI2 disconnected
[ 22.840] (II) intel(0): Output HDMI3 disconnected
[ 22.840] (II) intel(0): Output DP2 disconnected
[ 22.840] (II) intel(0): Output DP3 disconnected
[ 22.840] (II) intel(0): Using fuzzy aspect match for initial modes
[ 22.840] (II) intel(0): Output LVDS1 using initial mode 1152x864
[ 22.840] (II) intel(0): Output VGA1 using initial mode 1152x864
DistroRelease: Ubuntu 12.04
Package: xorg 1:7.6+7ubuntu7
ProcVersionSignature: Ubuntu 3.2.0-7.13-generic 3.2.0-rc7
Uname: Linux 3.2.0-7-generic x86_64
Date: Sat Jan 7 11:43:17 2012
DistUpgraded: Fresh install
ExtraDebuggingInterest: Yes, whatever it takes to get this fixed in Ubuntu
Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller [8086:0126] (rev 09) (prog-if 00 [VGA controller])
Subsystem: Lenovo Device [17aa:21dd]
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64 (20120106)
MachineType: LENOVO 7859CTO
PATH=(custom, no user)
LANG=en_AU.UTF-8ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-7-generic root=UUID=a63e6aba-2cae-4941-a76d-cf5be29c6655 ro quiet splash vt.handoff=7
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.version: 8GET33WW (1.10 )
dmi.board.version: Not Available
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.version: Not Available
dmi.product.version: ThinkPad L520
version.compiz: compiz 1:0.9.6+bzr20110929-0ubuntu8
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.29-1ubuntu1
version.libgl1-mesa-dri: libgl1-mesa-dri 7.11-0ubuntu4
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 7.11-0ubuntu4
version.xserver-xorg-core: xserver-xorg-core 2:1.10.4-1ubuntu6
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev 1:2.6.0-1ubuntu13
version.xserver-xorg-video-ati: xserver-xorg-video-ati 1:6.14.99~git20110811.g93fc084-0ubuntu1
version.xserver-xorg-video-intel: xserver-xorg-video-intel 2:2.15.901-1ubuntu4
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau 1:0.0.16+git20111201+b5534a1-1
Created attachment 55863 [details]
Created attachment 55864 [details]
Created attachment 55865 [details]
Created attachment 55866 [details]
(These are copied from the Launchpad bug - I figure they would be of use here.)
I did a dist-upgrade of my machine, as well as installing the latest Kernel you linked and have some interesting results:
1) I now need the 'noapic' flag in my boot options again.
Is this the same bug, or a different issue?
I have another bug open about this already: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/903558
2) The 'xrandr --output LVDS1 --off; xrandr --output LVDS1 --auto' command succeeds in turning on the other monitor some times. Compiz keeps crashing through, but it does switch on occasionally.
3) I did some testing with the Display settings and my Laptop monitor works on 1360x768 and smaller, but the two larger resolutions, 1440x900 and 1600x900 don't work.
I just did an upgrade and have discovered that if I boot into 12.04 with a second monitor, go into the Display Settings, ensure my laptop monitor is enabled with the right reso (1600x900), clicking 'Apply' switches on the monitor!
But it appears it will only switch on when the external is enabled too, so I can't make it happen without an external monitor there and activated.
So I guess the question is, why can't it start up the monitor on boot?
Hm, that's another report saying that plugging in a 2nd monitor and switching it on on snb machine magically fixes things ...
A few things: Can you upgrade your kernel to the latest drm-intel-fixes branch from Keith's git:
Also can you install intel-gpu-tools at least v1.1, hopefully ubuntu has it. Otherwise grab the latest git from:
Then run tools/intel_reg_dumper for both a working configuration (i.e. 2 monitors switched on) and a non-working configuration and attach the output to the bug. Please also attach the xrandr output so we know exactly what output configuration the register dump is coming from.
The noapic issue is likely unrelated to your gpu woes.
> Also can you install intel-gpu-tools at least v1.1, hopefully ubuntu has it.
I've updated the intel-gpu-tools package in Ubuntu to v1.1. You should be able to install or upgrade it through apt normally.
I also asked the kernel team to start making builds of the drm-intel-fixes (instead of drm-intel-next-proposed, which seems to have stagnated lately.)
URL for that kernel PPA:
I have just upgraded my Kernel and the primary laptop monitor now loads up on boot without any issues!
I still need to test the 'noapic' flag to see if it has been fixed too, but the important thing is, I can now use my laptop as a laptop :)
Do you still want all that debugging information, or should I not worry since it's now working?
The version I upgraded to is:
linux-headers-3.3.0-994-generic_3.3.0-994.201201290428_amd64.deb 29-Jan-2012 09:37 943K
linux-headers-3.3.0-994_3.3.0-994.201201290428_all.deb 29-Jan-2012 09:29 11M
linux-image-3.3.0-994-generic_3.3.0-994.201201290428_amd64.deb 29-Jan-2012 09:37 36M
I've tested and I still need the 'noapic' flag to successfully boot.
Can someone point me in the right direction to get this one fixed?
I will update my launchpad bug (https://bugs.launchpad.net/ubuntu/+source/linux/+bug/903558) with fresh details regarding this issue - but I don't know if it's in the right place to be noticed.
Nope, no more debug information needed. We've fixed quite a few bugs for snb lately and luckily yours was among them!
Closing resolved+fixed. No activity on ~4 years.