Comment 10 for bug 1637733

I'm also trying to run 16.10 desktop Ubuntu on a P651rp6-g laptop and I'm experiencing the same issue. I have MSHYBRID option selected in the UEFI, I'm using the UEFI rather than legacy Bios.

I'm currently using two ppas, the https://launchpad.net/~graphics-drivers/+archive/ubuntu/ppa with nvidia 378 drivers and the latest mesa from https://launchpad.net/~paulo-miguel-dias/+archive/ubuntu/poppa.

Just to note that this problem still exists with our without these ppas and with our without the proposed updates. I've also had to add GRUB_GFXPAYLOAD_LINUX=text to grub as otherwise I can't even complete the boot under UEFI as the screen just turns on and off.

It definitely seems to be related to lightdm somehow as issuing service commands against lightdm from the console, especially after changing the GPU with prime select results in the same symptoms

This bug report seems to highlight some very similar issues and behaviours:
https://bugs.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/1569383