So here was my PM:
So about my issue, to say in a few words, i have a p377sma PREMA bios with 1070n ( non gsync vbios )
In the beginning, i had sli 980m with an lg edp 120Hz 1080p display.
I upgrade it to a 2160p auo display with a custom cable i made. it was working perfectly, only hotkey for brightness wasnt working, but a little regedit in nvidia to allow brightness control from windows or control center was the solution. ( hotkey is for keyboard fn+f8-9 )
All drivers were working.
Then i decide to upgrade to 1070n msi gpu.
SO, when nvidia driver is not installed, it is "working" i mean i can do everything without any gpu requirment since intelhd are desactivated in our laptop. As the gpu is unknow in system, i need to mod .inf driver and to start laptop with driver without signature ( f7). Once i am in driver menu, once i click "accept this unofficial driver display", screen goes black. i still can contorl the fn+f2 ( to disable/enable backlight )well sometimes it is not working. if i wait a bit and shutdown laptop and i restart it. screen is still black, i can use hdmi with a projector and driver are installed. but display is not detected. not detected in hwinfo, in regedit, in windows or nvidia, no where. If i disable driver nvidia in device manager and restart the laptop screen is working BUT once i go in device manager to enable driver, screen go black. If i shutdown and replace my old lg 120Hz screen, it is first bugging with a black screen then the second restart, the screen work. i can shutdown, resart, enable/disable driver in device manager, lg screen work perfectly.
In linux, my 2160p is recognized with nvidia driver, so far so good with linux. Even the 1440p.
In windows 7 or 8, same issue, blackscreen with nvidia driver installed or during installation at the precise moment when i accept this unsigned driver to be installed.
i tried with a new 1440p 120Hz display, it give same black screen.
My system is not gsync, my gpu in begining was gsync ( same error ) then updated to a non gsync ( same error ). My lg display is not gsync. Both 1440p 2160p are gsync.
i tried some trick but it didnt work:
i tried while lg 120hz plugged to switch with one auo but laptop shutdown for security reason i guess ( detect screen removed) or i tried with hdmi connected, to disable screen laptop ( lg) then sleep mode), switching display then start and enabling, black screen too but detected but nothing can be done, i mean cannot change resolution or idk, it stay black.
i wanted to switch edid in linux but my system is wierd, cant detect in i2c pin to change display edid.
One day i "succeed " something, i suuceed with an old driver while lg 120Hz installed. i sleep mode the laptop, switch screen, then something appear on the AUO 4k, but half of the display work, and this half of display was like divided in 4 little display look this picture. ) other than that, nothing else...
This bug in display is what happen after driver installed or when i booot laptop with an auo display. But big majority (95%) is not so buggy like that, it just a green line upside for a few seconds.