I have Xubuntu 14.10 (x64) installed on my HP ProBook 6470b and experienced that the laptop suspends on closing the lid while it should only lock the screen. I found several complaints on forums that xfce-power-manager-settings doesn't perform well, so I made a change to the /etc/systemd/logind.conf file:
"HandleLidSwitch=ignore".
Now if I close the lid, it locks the screen as expected. When opening and entering the correct password for the same user, the screen goes black. I can log into each user account only once and cannot return to any open session after locking the screen. Restarting lightdm works but is not a solution for programmes with unsaved work.
The system also prompts for password when resuming from suspend, but that works alright.
On my HP Pavilion dv6205us laptop,
Xubuntu 14.10 (x86),
without changing /etc/systemd/
having setting xfce-power-manager to lock the screen when laptop lid is closed,
I have a similar problem:
When I close the lid, the laptop suspends (this is another bug). After resuming and entering the password, it shows black screen, just like my Probook with. I ran ubuntu-bug for this machine also.