Ctrl/alt/t
log in
password
sudo stop gdm
sudo dpkg-reconfigure lightdm
Now choose lightdm
Use tab key and arrows and enter key.
sudo /etc/init.d/lightdm restart
Should bring you to login screen and all should work.
On upgrade you still have gdm installed which is what lightdm does in oneiric.
In fresh install no gdm is installed.
You are just configuring to lightdm and the restarting it.
Ctrl/alt/t
log in
password
sudo stop gdm
sudo dpkg-reconfigure lightdm
Now choose lightdm
Use tab key and arrows and enter key.
sudo /etc/init.d/lightdm restart
Should bring you to login screen and all should work.
On upgrade you still have gdm installed which is what lightdm does in oneiric.
In fresh install no gdm is installed.
You are just configuring to lightdm and the restarting it.