Comment 21 for bug 1637733

This also affects me on a Clevo P950HP with:
- Kaby Lake i7-7700HQ
- NVIDIA GTX 1060 w/ 384.69 driver (binary installed via 'Additional Drivers' in Software & Updates menu)
- Intel HD Graphics 630, i915 driver w/ latest KBL firmware (via https://01.org/linuxgraphics/downloads/firmware)
- Xubuntu 17.04
- Kernel 4.12.14-041214-generic (via http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.12.14/)

The NVIDIA driver + card works fine, but selecting intel in the NVIDIA X-server or running prime-select intel causes the system to hang on shutdown, or at login after forced power-off, at the point when LightDM is loading.