Re: Display Port doesn't work until after OS loads
2020/02/29 13:03:41
(permalink)
The issue is most likely with the graphics card.
Nvidia released a tool to fix the displayport 1.3/1.4 compatibility issue. I just ran it on my 1080 Ti and it fixed the issue 100% where no boot screen would show when booting with CSM disabled.
Search: Nvidia Graphics Firmware Update Tool for DisplayPort 1.3 and 1.4 Displays