When I start X11 XORG 2:2.99.917+git20161206-1 on Gigabyte H67A-UD3H motherboard (without an external video card), GDM hangs (and is frozen) on startup. It may happen either before or after the background of the GDM screen is initialized, so I see either the frozen Linux console or the frozen GDM background without anything drawn on it.
I use 64 bit Linux kernel with 32 but userland.
Is the machine completely frozen? Can you grab dmesg and Xorg.log?
The machine seems completely frozen.
I don't know how to get dmesg of frozen computer. I also don't know how to find the appropriate log.
I have already inserted a Nvidia video card and cannot reproduce the bug, without disassembling my computer.