I have exactly the same problem on a Lenovo ThinkPad T410 running Xubuntu 18.10.
After the kernel upgrade to 4.18.0-14, the system would not display any graphical output after the Grub2 menu. However, from the HDD activity LED I can tell that the system boots ups once I enter my LUKS-password correctly. I can also shut down the system via SysRQs (Alt+PrintScreen+… – again clear responses from the HDD-LED and finally reboot).
Unfortunately, I didn't keep any older kernel. Reinstalling Xubuntu 18.10 fixed the problem, upgrading to the most recent kernel caused the problem to appear again (but this time I kept an older one).
I have exactly the same problem on a Lenovo ThinkPad T410 running Xubuntu 18.10.
After the kernel upgrade to 4.18.0-14, the system would not display any graphical output after the Grub2 menu. However, from the HDD activity LED I can tell that the system boots ups once I enter my LUKS-password correctly. I can also shut down the system via SysRQs (Alt+PrintScreen+… – again clear responses from the HDD-LED and finally reboot).
Unfortunately, I didn't keep any older kernel. Reinstalling Xubuntu 18.10 fixed the problem, upgrading to the most recent kernel caused the problem to appear again (but this time I kept an older one).