Temporary black screen after login

[Sergio Benjamim]

I turn on my laptop, wait lightdm appears, and do login to my user. Sometimes i got a black screen, only cursor appears in the screen. I can open a terminal with Ctrl+Alt+t, and run firefox using terminal, for example. And it is possible to change tty. Then, after 30 seconds, or more, like 1 minute, my desktop appears (background, unity launcher, top panel...).

I'm having this problem in my asus laptop, that have nvidia optimus (and can confirm with other, a sony laptop with only intel graphics card).

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: lightdm 1.8.4-0ubuntu1
ProcVersionSignature: Ubuntu 3.11.0-17.31-generic 3.11.10.3
Uname: Linux 3.11.0-17-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.2
Architecture: amd64
Date: Wed Feb 19 00:52:59 2014
InstallationDate: Installed on 2013-12-13 (67 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Release amd64 (20131016.1)
MarkForUpload: True
SourcePackage: lightdm
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

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

[Krasimir Kostadinov (krasimir-k)]

This is happen only with VGA connected monitor. With HDMI, I don't have the problem.

[Jesse Knight (jesseknight)]

This happens to me too (still) : both VGA and DVI-D (cannot test HDMI).
This happens at both log-in and log-out.

DistroRelease: Ubuntu 16.04
Architecture: amd64
Date: Sat Mar 10 2018