Hereby the ouput of journalctl attached in info.txt. Hope It gives you some clues.
** Attachment added: "info.txt" https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1448616/+attachment/4385839/+files/info.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1448616 Title: xubuntu15.04 goes into sleep after power-up To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1448616/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs