hdmi video out broken on package upgrade

[Theron Muller]

I have two external monitors, one running through the vga out port and the other the hdmi out port and both were working fine in a dual head configuration until a recent package upgrade. Now only the vga out works and in the dispaly manager the hdmi connected monitor does not appear.

I have another open bug about triple head not working here: https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-ati/+bug/931240 (laptop monitor won't work in tandem with two external monitors) but this is the first time for my hdmi out to go dead.

I've tried creating a new account to see if it was user specific settings creating the problem, but a new user account exhibits the same behavior.

I would like to know which package upgrade I need to reverse in order to get my workstation back to full functionality.

ProblemType: Bug
DistroRelease: Ubuntu 11.10
Package: lightdm 1.0.6-0ubuntu1.7
ProcVersionSignature: Ubuntu 3.0.0-21.35-generic 3.0.32
Uname: Linux 3.0.0-21-generic x86_64
ApportVersion: 1.23-0ubuntu4
Architecture: amd64
Date: Mon Jun 18 13:10:43 2012
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111011)
SourcePackage: lightdm
UpgradeStatus: No upgrade log present (probably fresh install)

[Sebastien Bacher (seb128)]

Thank you for your bug report, that's not likely a lightdm bug though, the login manager has little to do with the video out and there was no recent update for it, could you check you /var/log/dpkg.log to see what got updated when the issue started?

[Theron Muller (theron)]

This is the contents of dpkg.log from 2012-6-14 through 16. On the 14th there was a Linux kernel upgrade. That's the only thing I can recognize as potentially being problematic.

I tried to set the bug to gnome-display-settings, but that package appears to no longer exist. I'm not sure how to refer to the display settings tool from within system settings, and doubt it's a problem with that tool anyway; on startup the hdmi interface monitor is blank, and in the past it mirrored the vga monitor's startup splash screen.

[Sebastien Bacher (seb128)]

system settings is gnome-control-center, though it's just uis to set do configuration, gnome-control-center is not running at boot nor setting any screen resolution if you don't start the ui and act on the control so not likely the issue there

Could you try to boot the previous kernel and see if you still get the issue?

[Byron Palmer (byronpdx)]

I was using my laptop to play movies on my tv using hdmi. When I upgraded recently, which included a new kernel, the hdmi causes the computer to freeze, forcing a reboot. As long as I don't plug in the hdmi everything works properly. But the instant I plug in the cable the computer freezes. The wifi continues to function but nothing else. I can't switch to a terminal screen. The only thing I can do is reboot.

I have not tried going back to an earlier kernel but will try that soon.

[Sebastien Bacher (seb128)]

@Byron: your issue seems a kernel issue, report it using "ubuntu-bug linux" after having the issue (i.e reboot and run that command)

[Theron Muller (theron)]

Turned on the computer this morning and hdmi was mysteriously working again. Thanks for all your suggestions for help and patience. Please feel free to close this bug. I will myself if I can figure out how.

[Theron Muller (theron)]

I'm not sure which status to change the bug to, so will let you close it, Sebastian. Thanks again for your assistance. I really appreciate it.

[Sebastien Bacher (seb128)]

thanks for the update, setting to invalid to follow the previous comments