BUG: Blackscreen when OS starts up a Display Manager after initramfs

[feeRnt]

-- System Information: CUH-1216 Belize B0(0x20200)
-- Firmware: 9.00
-- Exploit: PSFree + Lapse -> Goldhen -> Ps3itaTeam Linux Loader

-- OS: Arch Linux
-- Desktop Environment: xfce4 and others
-- Display Manager: lightdm and others

-- Affected branch: ps4-linux-6.15.y

When the kernel goes from the initramfs TTY to a graphical.target startup, and so launches a display manager, it leads to a black screen.

When the OS loads into a display manager, it seems to ask for a new mode refresh.. and that's when it gets this blackscreen.
The graphics stack (DRM, AMDGPU) asks for a new display mode, which is essentially the vertical refresh rate, monitor clock, y dimension, x dimension etc. info used to output an image to the monitor.

It seems to need an HDMI cable unplug+replug sequence to fix, or something that is equivalent (such as changing my Samsung monitor's FreeSync setting). Afterwards, you need to switch to a different TTY by pressing Ctrl+Alt+F3, and then pressing Ctrl+Alt+F2 or F7, whichever is the TTY of your GUI, to fix your display.

But surprisingly, subsequent mode switchups/refreshes don't need a replug..

I have heard that this issue didn't exist on the older kernel versions (4.14 and maybe 4.19), but all subsequent versions do.