Daniel, yes that one line fixes the bug. It's not a proper fix but a work-around for GDM3.
There's something about gdm-xsession being run that's different from LightDM that's not triggering the nvidia modeset drivers to turn detect external monitors and enabling PRIME sync. I discovered the workaround after accidentally doing a sudo startx and noticing that both PRIME sync and my external monitor had been enabled. As this is quite an innocuous fix, would it be possible to upstream this into the Ubuntu GDM3 codebase until the GDM3 maintainers decide that it would be worth their time to actually look at this bug seriously and fix it in their codebase? Otherwise it gets annoying having to patch the systemd service everytime GDM3 gets a point update. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1716857 Title: gdm3, hybrid nvidia with modeset=1, no external monitors detected To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gdm3/+bug/1716857/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs