Recently I had to reinstall my ubuntu 12.04 due to some kernel installation issues. So i grabbed a new livecd and installed it. Went on to configure drivers and settings. I have bumblebee installed to handle the Nvidia 620M for 3D applications and the Intel HD4000 cpu integrated chip to do desktop environment and such.
THe issue being is after bumblebee was installed i didn’t see the login in screen anymore. But i heard the login screen sound so i typed in my password hit enter and voila it works. I want to fix this though what i have found so far is.
In virtual console starting lightdm returns with Failed to use bus name org.freeDesktop.DisplayManager do you have the appropriate permissions ?
I've looked around and cant find a solution similar problem i've seen like this was just unity to starting at all mine starts but only after logging in .
If I need to supply additional info please tell me so and I will do so.
Another discovery/insight. Turning on ALPM https://wiki.ubuntu.com/Kernel/PowerManagementALPM cause's the screen to be black on launch as well as the device isn’t properly called. Also has weird side effect on the wifi.
So i have it "FIXED" What i did is was a 12 hour wild goose chase around ubuntu ^^ In all seriousness I reinstalled to make sure it a a reproduce-able issue. After confirming it was I went into /etc/bumblebee/xorg.conf.nvidia and added my PCI BusID of my video card. This was to make bumblebee work. After I done this I had the same issue again. After some research I changed line 15 in /etc/bumblebee/bumblebee.conf TurnCardOffAtExit=false into TurnCardOffAtExit=true.
Now everything works as far as I can tell have to do some more testing. Another issue i have now even before bumblebee is that loging in takes ages(20+ sec). Would be nice if someone has an idea what that does.
EDIT: This does bring up the question that 620M doesn’t work out of the box (Meh it's linux nothing does) but if you follow http://askubuntu.com/a/36936/229978 There is no mention of it.
EDIT 2: still broken open for any suggestions