When I close laptop lid, machine hibernates. But when I open the lid maybe an hour later and give a password screen lock asks, I can remove lock but screen turns blank. I guess screen lock doesn't tell to the powermanager that it should turn screen from blank state to showing desktop. If I remove locking feature, everything works well. I solved the problem by removing light-locker and installing xscreensaver as in my old Xubuntu installation. My installation was new, not upgraded from previous version, but home folder and settings are migrated from old Xubuntu 12.10 installation.
When I close laptop lid, machine hibernates. But when I open the lid maybe an hour later and give a password screen lock asks, I can remove lock but screen turns blank. I guess screen lock doesn't tell to the powermanager that it should turn screen from blank state to showing desktop. If I remove locking feature, everything works well. I solved the problem by removing light-locker and installing xscreensaver as in my old Xubuntu installation. My installation was new, not upgraded from previous version, but home folder and settings are migrated from old Xubuntu 12.10 installation.