I'm experiencing this bug after upgrading from kubuntu 14.10 to 15.04 using the update manager.
Using nvidia-346: Booting with a previous kernel (3.16) works but I'm stuck in intel mode. Booting with current kernel (3.19) leaves me with the black screen which can be fixed (until restart) by running the suggested: sudo systemctl stop sddm sudo systemctl start gpu-manager sudo systemctl start sddm Idk if its relevant but gpu-manager.conf : start on (starting lightdm or starting gdm or starting kdm or starting xdm or starting lxdm) task exec gpu-manager --log /var/log/gpu-manager.log Tried the obvious and added a line "or starting sddm" but didn't work :P ** Attachment added: "dpkg -s ubuntu-drivers-common.txt" https://bugs.launchpad.net/ubuntu/+source/ubuntu-drivers-common/+bug/1443364/+attachment/4383102/+files/dpkg%20-s%20ubuntu-drivers-common.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1443364 Title: gpu-manager systemd unit is not enabled To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ubuntu-drivers-common/+bug/1443364/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs