Getting a black/blank screen when switching between users in lucid

[Jeremy Yoder]

Binary package hint: fast-user-switch-applet

Not sure this is the right applet, but it seems to be affecting a number of people.

1) Ubuntu 10.04 LTS (lucid)
2) Unknown (I assumed fast-user-switch-applet, but I can't find a version number for it, so maybe this isn't part of Lucid?)
3) Switching between 2 users repeatedly should work
4) It fails after 1-3 switches with a black/blank screen

Steps to repeat:
- Boot ubuntu and login to user A
- Then Click on power menu (top right corner) and select: Switch from A
- I get the login screen
- I select user B and enter my password
- I hit ok
- I am able to login successfully to user B
- Now, I Click on power menu (top right corner) and select: Switch from B
- I select user A from the login screen and enter my credentials, then hit OK
- I get a black screen

Alternatively:
- Boot ubuntu and login to user A
- Then Click on power menu (top right corner) and select: Switch from A... Select B
- I get the login screen
- I hit ok
- I am able to login successfully to user B
- Now, I Click on power menu (top right corner) and select: Switch from B... Select A
- I get a black screen

In my case, Ctrl+Alt+F1-6 is black as well. The computer is NOT hung, I can type blindly and shut down fine.

More details:
http://ubuntuforums.org/showthread.php?t=1471915
http://ubuntuforums.org/showthread.php?t=1467619

Might be related to this bug reported against Jaunty?
https://bugs.launchpad.net/ubuntu/+source/fast-user-switch-applet/+bug/354083

[Jeremy Yoder (jyoder)]

The following workaround does restore the display:
Alt+F2
Type: xgamma -gamma 1.0

(for more displays you can use "xgamma -display 1.0 -gamma 1.0")

More possibly related bug reports:
https://bugs.launchpad.net/ubuntu/+source/indicator-session/+bug/549632
https://bugs.launchpad.net/ubuntu/+source/gnome-screensaver/+bug/555870
https://bugs.launchpad.net/xserver-xorg-driver-ati/+bug/546578

[Dallman Ross (spamless)]

I have this problem and the xgamma suggestion does not help.

I upgraded Karmic to Lucid on a 64-bit AMD platform. It's mostly okay (I don't like purple, though, and will have to delve into Plymouth.)

But when I try to log in under KDE instead of GNOME, I get the intro screen and music and then blackness. I can see the mouse, and that's it. I can type blindly or use known keyboard shortcuts, e.g., Alt-F2. Otherwise, I'm lost. I'm able to log out and log back in to GNOME with no problem.

[Dallman Ross (spamless)]

Okay, my own problem is solved and may be unrelated to the others. Or not. :-)

Mine was, I had never fully installed KDE. Duh. So that explains why when I tried logging in to it I got a black screen.

I'm now in it typing this after installing it via Synaptic Package Manager.

[David Tombs (dgtombs)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. This particular bug has already been reported and is a duplicate of bug 546578, so it is being marked as such. Please look at the other bug report to see if there is any missing information that you can provide, or to see if there is a workaround for the bug. Additionally, any further discussion regarding the bug should occur in the other report. Please continue to report any other bugs you may find.

[penalvch (penalvch)]

Jeremy Yoder, this bug was reported a while ago and there hasn't been any activity in it recently. We were wondering if this is still an issue? If so, could you please test for this with the latest development release of Ubuntu? ISO images are available from http://cdimage.ubuntu.com/daily-live/current/ .

If it remains an issue, could you please run the following command in the development release from a Terminal (Applications->Accessories->Terminal), as it will automatically gather and attach updated debug information to this report:

apport-collect -p linux <replace-with-bug-number>

Also, could you please test the latest upstream kernel available (not the daily folder) following https://wiki.ubuntu.com/KernelMainlineBuilds ? It will allow additional upstream developers to examine the issue. Once you've tested the upstream kernel, please comment on which kernel version specifically you tested. If this bug is fixed in the mainline kernel, please add the following tags:
kernel-fixed-upstream
kernel-fixed-upstream-VERSION-NUMBER

where VERSION-NUMBER is the version number of the kernel you tested. For example:
kernel-fixed-upstream-v3.13-rc3

This can be done by clicking on the yellow circle with a black pencil icon next to the word Tags located at the bottom of the bug description. As well, please remove the tag:
needs-upstream-testing

If the mainline kernel does not fix this bug, please add the following tags:
kernel-bug-exists-upstream
kernel-bug-exists-upstream-VERSION-NUMBER

As well, please remove the tag:
needs-upstream-testing

Once testing of the upstream kernel is complete, please mark this bug's Status as Confirmed. Please let us know your results. Thank you for your understanding.

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]