Black screen after logging in after resume in Xubuntu 14.04

[MichiGreat]

Occasionally, when resuming Xubuntu 14.04 after hibernating it before, the screen is very dark. I must turn it bright with Fn+F5 then. After entering my password, I only see a black screen and I have to restart lightdm in order to be able to continue work.

$ lsb_release -rd
Description: Ubuntu Trusty Tahr (development branch)
Release: 14.04

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: lightdm 1.9.13-0ubuntu1
Uname: Linux 3.14.0-031400-generic i686
ApportVersion: 2.14-0ubuntu1
Architecture: i386
CurrentDesktop: XFCE
Date: Wed Apr 2 20:20:16 2014
EcryptfsInUse: Yes
InstallationDate: Installed on 2014-03-21 (12 days ago)
InstallationMedia: Xubuntu 14.04 LTS "Trusty Tahr" - Alpha i386 (20140225)
LightdmGreeterLog:
 ** (lightdm-gtk-greeter:1278): WARNING **: Failed to load user background: Datei »/home/michael/Downloads/Not_My_Tux_by_Twarrior.jpg« konnte nicht geöffnet werden: Keine Berechtigung

 ** (lightdm-gtk-greeter:1278): WARNING **: Failed to load user image: Datei »/home/michael/.face« konnte nicht geöffnet werden: Keine Berechtigung
 init: indicator-power-main-Prozess (1323) wurde von TERM-Signal beendet
 init: indicator-sound-main-Prozess (1325) wurde von TERM-Signal beendet
SourcePackage: lightdm
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Jan Drewes (j-launchpad01)]

I am experiencing the same problem. Xubuntu 14.04, all updates until 02.04.2014. My system is a lenovo x200 with intel graphics.

When I resume from suspend-to-ram, I get the password screen as expected, but at minimum screen brightness. This can be corrected with the screen brightness hotkeys. However, once I enter my password, the screen goes entirely black. I am not 100% sure, but I think it is the kind of black that you get when the backlight is off. At this point the only thing that works is to switch to a text console or use ssh to restart lightdm. Of course I loose all open windows this way, which makes suspending essentially useless.

The only exception I encountered was when I suspended while LibreOffice Impress was on full screen. That one time, resuming worked. I am not sure if it was related.

I have checked my logs but I did not find any resume-related errors. Please let me know if I should upload any logs etc.

[Jan Drewes (j-launchpad01)]

I found that apparently it had nothing to do with lightdm. It was a conflict between xfce-power-manager and systemd. This solution worked for me, suspend and resume now work:

http://ubuntuforums.org/showthread.php?t=2184892

[Malaise (malaise)]

On my Lenovo E530, disabling the handling of logind worked with Xubuntu 13.10.
It does not work with Xubuntu 14.04

[Gene475001 (gene-armistead)]

This solution also does not work with Ubuntu 14.04 on my Lendovo T61. I'm using the Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller. Doing this actually prevented my laptop from suspending. The screen would shut off when I closed the lid, but the laptop was still on. Opening the lid didn't turn on the display. I had to move the mouse or hit a key. After entering the password the screen still went blank.

[Christophe Lardinois (chrlardinois)]

Hi,

I'm facing the same problem on a fresh (25 march 2015) install of Xubuntu 14.04.2 LTS

Two more observations :

1) I started an audio streaming which stops when I close the lid (this is obvious). When I re-open the lid and push on the power button, the login screen comes back (no audio at this time, as the user's session is not active yet), then I login and the screen goes all black, but I can ear the audio. So the processes are still there and running ok. Just the screen stays black.

2) If, after having logged in back (the screen is annoyingly black), I connect another screen, then switch to this screen (yes, blindly ! I'm used to doing the manoeuvre, so I know the exact key combination to do this with the screen being black ... ) then, I see the desktop on the secondary screen. I then swith back to the primary screen using the same keyboard keys combination (Fn + f4 in my case) and the primary screen comes back to life !
Marvelous ! But this not acceptable for any lambda user, or if you don't have a second screen next to your laptop.

As mentioned by another user (I don't remember where), locking the session BEFORE closing the lid, avoids the black screen problem when returning.
But, again, this not acceptable as you quite often left your laptop without locking and come back 1 hour later and the laptop went to suspend mode without previously locking the session, again leading to the black screen problem.

Could you solve this problem once and for all ?

From my point of view, there are parameters spread all over about the power management, screen savers, screen lockers, etc ....
It would be a great thing to centralize all those parameters (from a user point of view) insuring there is no conflict between the many processes involved by all those parameters. I know this is easier to say than to do, but ... this is (I)MHO.

Many thanks for your great work, by the way !
Christophe.