Laptop does not wake up when running on batteries
After a clean install from Fedora 14 (KDE desktop), I could close the lid from my Thinkpad R500 and it would go nicely to sleep. And after opening the lid again, it would also nicely wake up.
Quite regularly I perform a yum update and I have remarked that after several updates the wake-up behaviour has changed.
When running on the adapter, the latpop goes to sleep and wakes up without problems.
When running on batteries, it does not matter if the laptop goes to sleep after a period of inactivity or because the lid was closed, it won't wake up without a hard reboot.
How can I restore the wake-up behaviour?