Created attachment 143690 [details]
The complete output of dmesg

Hello! 
Let me state right now that this is my first bug report and I am a little bit
lost about what criteria I have to fulfill and whether I am reporting for the
correct component.

My system:
I am using Arch Linux with the 5.0.1 Linux kernel.
I have a Thinkpad P1 laptop with an Intel 8750H and an NVidia Quadro P1000.

What happens:
Before I turn on my laptop, I connected my external display via HDMI. Then I
turn on my laptop and reach the bare tty (I am not using any Login Manager).
While the tty is displayed, a lot of kernel messages are printed to the
standard output about nouveau having some problems.
As soon as I try to login (which starts my Window Manager, Sway), the system
freezes and I have to hard reset my Laptop.

Workaround:
When I disconnect the HDMI cable before booting and connect it AFTER I logged
into my system, then my external display works correctly.

I dumped my whole dmesg output into the attached 'system.log' file, and I also
retrieved the VBIOS information for my external display, I think.

Let me know, if I can provide any further information and again, excuse any
noob mistakes.