Display rotation via kernel argument does not work

NVIDIA Open GPU Kernel Modules Version

575.64.03

Please confirm this issue does not happen with the proprietary driver (of the same version). This issue tracker is only for bugs specific to the open kernel driver.

• I confirm that this does not happen with the proprietary driver package.

Operating System and Version

NixOS 25.05

Kernel Release

6.15.6

Please confirm you are running a stable release kernel (e.g. not a -rc). We do not accept bug reports for unreleased kernels.

• I am running on a stable kernel release.

Hardware: GPU

NVIDIA GeForce RTX 3080

Describe the bug

I am using two main monitors, one of which is a vertical screen.
The vertical screen has the wrong rotation during boot and the TUI login manager (I use ly).

The kernel has "video=..." and "fbcon=..." options, to change the display rotation. Setting the "video=..." option had no effect with the open-gpu kernel module.

To Reproduce

1. Determine, which port the Display is on. I used xrandr --query for this.
2. Set the kernel parameter to one of the following: (Change the DP-3 according to your Port)
   "video=DP-3:rotate=90"
   "video=DP-3:panel_orientation=right_side_up"
   "video=rotate=90"
   "video=rotate=270"
   "fbcon=rotate:3"
   "fbcon=rotate:1"

Only the last two options have an effect. But they rotate all displays, not just one.

Bug Incidence

Always

nvidia-bug-report.log.gz

nvidia-bug-report.log.gz

More Info

There was discussion on this, while trying these options:
https://discourse.nixos.org/t/nvidia-rotate-display-via-kernel-parameter/66511/6

Start by reproducing the issue with the listed video=, panel_orientation, and fbcon= parameters, using xrandr --query to verify the connector name. Compare the per-display behavior of video= with the global rotation from fbcon= on the RTX 3080 setup; done means the vertical display has the correct rotation during boot and in the ly TUI login manager.