LightDM Error: (EE) no screens found, after Upgrade from 12.04 to 14.04 (ubuntu 64 Bit) no GUI available

[LinuxFreak]

Hello,

on 27.09.2014 i did a system upgrade from ubuntu 12.04 (64bit) to ubuntu 14.04.1. LTS (GNU/Linux 3.13.0-36-generic x86_64)
(A test with the Live DVD 14.04 LTS before the dist-upgrade, was sucessfully.)
After reboot there was no GUI, only the console. After a login, doing nothing at this state, after some minutes a white screen appears. Seems to be the screensaver.
Trying tharting the GUI with "startx" there were following errors:

...
...
...
Initialializing...
Initialializing built in extension DRI2
Loading Extension GLX
(EE)
Fatal Server Error:
(EE) no screens found(EE)
(EE)
Please consult the X.Org Foundation Support
(EE) please check the log in file "/var/log/Xorg.0.log"....
(EE)
(EE) Server terminated with error (1). Closing Log File
xinit: giving up
xinit: unable to connect to x server: Connectino refused
xinit: server error

lspci -nnk | grep "VGA\|'Kern'\|3D\|Display" -A2
says:

01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] RV620/M82 [Mobility Radeon HD 3450/3470] [1002:95c4]
 Subsystem: Hewlett-Packard Company Device [103c:3600]
 Kernel driver in use: radeon

xrandr --prop
says:
cannot open Display

regards AstroPhysik

[LinuxFreak (bwvienna)]

Here is the log file

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1376618/+editstatus and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]

[penalvch (penalvch)]

AstroPhysik, 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 as it will automatically gather and attach updated debug information to this report:

apport-collect -p xorg 1376618

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

As well, given the information from the prior release is already available, testing a release prior to the development one would not be helpful.

Thank you for your understanding.

Helpful bug reporting tips:
https://wiki.ubuntu.com/ReportingBugs

[Launchpad Janitor (janitor)]

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