Comment 17 for bug 1630245

I've tried now:
With Ubuntu 16.04.1 LTS:
- Plain vanilla kernels 4.1.x, 4.4.x, 4.7.10, 4.8.x
- Ubuntu-Kernels: 4.5-rc1, 4.5-final, 4.6-final
- fedora mainline kernels (only took kernel-config, compiled kernel myself)
  Result: keyboard, mouse working as expected with all kernels, except
          4.8.6 -- maybe there was a missing configuration option with
                   this kernel. I did not dig into it.

With Ubuntu 16.10:
- Plain vanilla kernels 4.1.x, 4.4.x, 4.7.10, 4.8.x
- Ubuntu-Kernels: 4.5-rc1, 4.5-final, 4.6-final
- Fedora mainline kernels (compiled using Ubuntu 16.04.1 LTS)
  Result: no keyboard, no mouse for all kernels. But to be exact:
  Boot. Wait for Login prompt. For a short time the cursor is
  blinking behind "login:". While the cursor is blinking there, you
  can type! If you are fast, you may even press return, and
  "Password:" pops up. If you have a short password you may now
  be able to type this password and log in. In most cases at some
  point the cursor just vanishes and no further keypress is accepted,
  including CTRL-ALT-DEL. You are locked out.

  This is for all kernels I tested. It does not depend on some special kernel.

With the help of SystemRescueCD I've booted up and analyzed the logs written by systemd: Systemd starts consoles. Then, after starting some further parts of the system, terminates consoles. I could not find any console starts afterwards. I'd expect systemd to restart any terminated console for as long as systemd runs. This does not happen. Systemd is configured to restart consoles, but it does not do it. I was not able to find out why.
Networking is started but it seems not to establish network connections until users log in. In tune sshd never starts, because network isn't started at all. If you manage to login typing really fast, while the cursor blinks behind "login:" networking will start! You may be locked out at consoles, because no keypresses are accepted any more, but in case you managed to login, NetworkManager starts networking for the logged in user and in tune sshd is started and you may then login remote.