I have been trying to work out how to log a failed session with plymouth debug messages. I finally succeeded, it is attached. Note that at the end of log file, it goes into suspend. That was me trying to power off the machine, and not holding the button long enough. It actually suspends and resume right back to the stuck plymouth display, but I don't know any way out except to force the machine off.
** Attachment added: "Boot log including plymouth trace messages" https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1872159/+attachment/5353608/+files/plymouth_fail.txt -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1872159 Title: booting with splash hangs when external monitors are connected (pure intel 8th gen laptop) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/plymouth/+bug/1872159/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs