Black screen on switching users

[Wadelius]

I have an Asus UX303LN with Ubuntu 15.04. There are two user accounts, one administrator and one that is not administrator.

When I switch between users the screen turns black, sometimes the windows the user has opened are flashed before it turns black. If I hold the laptop against a bright light I can see that the windows are there, but that the back-light is completely switched off. When I close the lid and open again, making the laptop going into suspend and back, the back-light is on. When coming back from suspend I'm greeted by the login screen, but while I write my password it goes into suspend again. Pressing space or closing and opening the lid brings up the login screen and I can successfully login
Summary:
- Log in user A
- Switch to user B
- Switch back to user A -> Windows that are open flash then black screen
- Close the lid and open again -> login screen
- While writing the password the laptop goes to suspend. Hitting space brings is up again.
- Attempt to login -> screen is not black.

I have also found that the user switched to is not critical, as long as the switch user screen has been triggered:
- Log in as user A
- Press the cogwheel in the upper right corner, select user B.
- When prompted with user Bs password, change your mind and switch to user A again.
- The same black screen behaviour as above.

So it seems that the culprit is something triggered by the switch user screen, that differs from just locking one account and entering the password to it.

This or similar issues have been reported before, as far back as 2010 it seems. I have not found any solution by reading threads, it seems that sometimes people get lucky and the issue disappears during an upgrade.

To get the touchpad and other stuff working I have as recommended in the following thread added a couple of PPAs.
Thread: http://ubuntuforums.org/showthread.php?t=2243162
PPAs:
http://ppa.launchpad.net/xorg-edgers/ppa/ubuntu
http://ppa.launchpad.net/hanipouspilot/focaltech-dkms/ubuntu
Other PPAs to get applications I want:
http://ppa.launchpad.net/nilarimogard/webupd8/ubuntu
http://repository.spotify.com
http://apt.insynchq.com/ubuntu
http://download.virtualbox.org/virtualbox/debian

[penalvch (penalvch)]

Wadelius, thank you for taking the time to report this bug and helping to make Ubuntu better. Please execute the following command, as it will automatically gather debugging information, in a terminal:
apport-collect -p xorg 1492815

Please ensure you have the package xdiagnose installed, and that you click the Yes button for attaching additional debugging information.

When reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

[Launchpad Janitor (janitor)]

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