My Unity Greeter/LightDM is working fine in Precise with one exception.
When the greeter first displays the default system wallpaper /usr/share/backgrounds/warty-final-ubuntu.png is visible for 1 second, before dynamic LightDM kicks in. Its more of a nuisense than anything, but what options do I have to configure this to make it run seamlessly?
I have looked at other related AU Q&A and UF with no success and I have reviewed the configuration at
gksu gedit /etc/lightdm/unity-greeter.conf
Change the wallpaper to match your "dynamic" backgoroud or, change it to - something like a black, or dark purple background so you don't notice the switch, How do I change the wallpaper of the login screen? , otherwise you will notice when it changes from the default to your dynamic.
Maybe its a bug, who knows? If you turn off the dynamic wallpaper it will still show a transition from a purple background to a custom wallpaper.
Note to benefit others: Answer accepted as it improved LightDM transition, however it did not fully resolve the issue. Complete resolution would be nice, its a "paper over the cracks" solution (the black background).