Same symptoms(*) here after a fresh upgrade to 18.04. Tried installing gdm, as suggested above, and also adding "xrandr" as suggested, here: https://forums.fedoraforum.org/showthread.php?316354 -SDDM-shows-black-screen-with-Nvidia . Neither made a difference for me.
However, the problem finally went away after switching to the nouveau driver. (And I have no recollection of ever asking for the proprietary nvidia driver, specifically, but I may be wrong about that.) (*) Symptoms: sddm, but also lightdm and gdm3 showing only black. startx brings up an xfce session without problems. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to apt in Ubuntu. https://bugs.launchpad.net/bugs/1765923 Title: Nvidia driver leads to black screen on bionic 18.04 SDDM LightDM bug? Status in apt package in Ubuntu: Confirmed Status in nvidia-graphics-drivers-390 package in Ubuntu: Confirmed Status in sddm package in Ubuntu: Confirmed Bug description: Using the April 19th daily build of Kubuntu 18.04 I installed the Nvidia drivers via the following command. sudo ubuntu-drivers autoinstall The install process proceeds fine and after a logout process I get a black screen. I tried this on the April 17th daily build of bionic and a reboot also results in a black screen. The following is a question which was submitted by a Ubuntu 17.10 user: QUOTE After I installed latest Nvidia driver-390 and tried to boot after shutting down once I faced a black screen problem. since, I'm a noob but something related to nvidia drivers couldn't be started. Then I followed https://askubuntu.com/a/968692/802490 While following these instructions re-installing of nvidia drivers failed. The only things that worked is purging the drivers and changing "WaylandEnable=false" in (/etc/gdm3/custom.conf). Now, I want to re-install nvidia drivers again but I'm afraid that this will lead to that problem again. Can anyone help in re-installing the driver such that I won't face that problem? END QUOTE THE WORK AROUND Use Ctrl-Alt-f6 to get to a login prompt. Login run "startx" The x server will start and Nvidia drivers will function. THE PROBLEM When I try to run SDDM I get an error (Which I will try to copy down to add to this bug when I am on a different computer than the one I am reporting the bug about.). Installing lightDM does not work... it installs but is either will not run or will not actually start a x session. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/apt/+bug/1765923/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
