Zeno Brighenti

Dear all, I installed Peppermint this Monday and everything works great. There is just one annoying issue that i've encountered so far. When i close my laptot's lid, in battery mode, the system effectively suspends itself. But when i open it, after prompted my username and password on the log-screen, the screen suddenly becomes all black (no way to bright it to light with the keyboard by the way, which usually it works in normal condition), even if from the speaker sounds is still coming out (i.e...