I was able to get LightDM (or GDM) with hybrid graphics only by manually specifying an /etc/X11/xorg.conf file like follows (I generated it with nvidia-xconfig and then made manual modifications following this [1]):
# nvidia-xconfig: X configuration file generated by nvidia-xconfig # nvidia-xconfig: version 440.64 Section "ServerLayout" Identifier "Layout0" Screen 0 "Screen0" InputDevice "Keyboard0" "CoreKeyboard" InputDevice "Mouse0" "CorePointer" EndSection Section "Files" EndSection Section "InputDevice" # generated from default Identifier "Mouse0" Driver "mouse" Option "Protocol" "auto" Option "Device" "/dev/psaux" Option "Emulate3Buttons" "no" Option "ZAxisMapping" "4 5" EndSection Section "InputDevice" # generated from default Identifier "Keyboard0" Driver "kbd" EndSection Section "Monitor" Identifier "Monitor0" VendorName "Unknown" ModelName "Unknown" Option "DPMS" EndSection Section "Device" Identifier "Device0" Driver "nvidia" VendorName "NVIDIA Corporation" BoardName "GeForce GTX 1650 with Max-Q Design" BusID "PCI:1:0:0" EndSection Section "Device" Identifier "Device1" Driver "intel" VendorName "Intel" BusID "PCI:0@0:2:0" Option "AccelMethod" "SNA" EndSection Section "Screen" Identifier "Screen1" Device "Device1" EndSection Section "Screen" Identifier "Screen0" Device "Device0" Monitor "Monitor0" DefaultDepth 24 Option "AllowEmptyInitialConfiguration" "True" SubSection "Display" Depth 24 EndSubSection EndSection Are you using a similar configuration for X or it just works for you out of the box? About the BIOS, I checked and "Set Optimized" was Disable for me, turning it to Enable seems to make me able to reboot with a Thunderbolt adapter connected to the port. Many thanks for your help! [1] https://gist.github.com/alexlee-gk/76a409f62a53883971a18a11af93241b -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1876741 Title: Lenovo X1 boot crash with HDMI cable attached and laptop lid closed To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1876741/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs