When I recently upgraded Light DM got installed and i had configured it instead of KDM and was facing issues while boot.
Boot process stops at Checking Battery / Laptop-Mode...
I had to sudo kdm to access my desktop (Got to the console by pressing CTRL ALT F1 ) .
Now I have reverted to kdm to avoid the issue. I must admit the LIght DM did look as a good alternative to KDM. Unfortunately was facing the issue.
I run LM 13 KDE.