So I've been fiddling with getting my graphics card switching working on my Sager laptop with bumblebee/optirun/etc. I finally got that working but I managed to break my display manager startup and I can't figure out why.

This is on Debian 10 on a Sager NP6852.

So when I start up the laptop in multiuser.target I log in as myself, startx and X loads fine to my default of cinnamon. If I switch to graphical.target and reboot the screen hangs and essentially the laptop hangs entirely... can't do anything.

I can't find anything in the logs showing why it locks up and won't boot... I see some errors of "The X11 connection broke (error 1). Did the X11 server die?" and "[ 21.980406] traps: light-locker[1057] trap int3 ip:7fdf800e2c75 sp:7ffe3ad475e0 error:0 in libglib-2.0.so.0.5800.3[7fdf800aa000+7e000] " in dmesg but that's about it that looks concerning.

I've tried reconfiguring which dm I'm using, no dice. Any ideas??

I will add, I had to mess around a TON with drivers/config to get this to work. Currently running on the Nvidia 440 .run from their website. /etc/X11/xorg.conf is X.org configured and works fine when running a startx as a user.

try a simple one like slim? debian and system D hum I left debian long before that so that is all of what I got to suggest. using systemD for enabling and disabling software commands, and does not systemD gota command to ask it, whats up, yo, why isn't this thing working?

on some OS without systemd, not many but I've edited startx changed
to = 0

that is just a really big shot in the dark on your situation.

The only issue I have with that is that startx works fine from a multiuser env. So I log in on the command line as myself and startx works fine. It's when I change it to graphical boot to load lightdm or whatever that it literally locks up and never boots completely to the login screen. So the issue doesn't seem to be with startx?

Here's a screenshot of where it hangs on boot. I don't get those errors at the very bottom any other time other than when it's trying to start the login manager.

I've never seen a login manager cause a kernel panic before.

put it in Debian bug listing maybe they can help, as it seems no Deb-heads in here are willing to try and help you tackle this.