After unlocking, desktop is shown then screen goes black for about five seconds

[Burt P.]

After entering a password to unlock the computer the desktop is shown and is usable for about 1 second, then the screen goes black for 5 seconds or so, then return to normal.
Using NVIDIA drivers 331.38 from the package nvidia-331.

$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu Trusty Tahr (development branch)
Release: 14.04
Codename: trusty
$ apt-cache policy lightdm
lightdm:
  Installed: 1.9.14-0ubuntu2
  Candidate: 1.9.14-0ubuntu2
  Version table:
 *** 1.9.14-0ubuntu2 0
        500 http://us.archive.ubuntu.com/ubuntu/ trusty/main amd64 Packages
        100 /var/lib/dpkg/status

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: lightdm 1.9.14-0ubuntu2
ProcVersionSignature: Ubuntu 3.13.0-23.45-generic 3.13.8
Uname: Linux 3.13.0-23-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.14.1-0ubuntu1
Architecture: amd64
CurrentDesktop: Unity
Date: Mon Apr 7 14:45:47 2014
InstallationDate: Installed on 2014-01-04 (93 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
SourcePackage: lightdm
UpgradeStatus: Upgraded to trusty on 2014-03-09 (29 days ago)

[Launchpad Janitor (janitor)]

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

[Thilo Cestonaro (tephraim)]

it's like the screensaver doesn't work in the lock screen but wants to black the screen anyway.
So after the lockscreen is done (unlocked again), the screensaver remembers that it should have blacked the screen and does it then. After hitting a key, the screen comes back normaly. You haven't to wait.
My graphic:
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)

So not NVIDIA specific.

Cheers,
Thilo

[Thilo Cestonaro (tephraim)]

Killed gnome-screensaver => old lockscreen is back, but when unlocking, no black screen afterwards anymore.

[Thilo Cestonaro (tephraim)]

No black screen anymore. For me, this bug is fixed.

Cheers
Ephraim