Multiple monitors stuck at low resolution with HDMI→DP adapters on NVIDIA

General
1

Hi,

I recently installed CachyOS and I’m having issues with multiple monitors being detected at incorrect resolutions.

Hardware:

  • NVIDIA RTX 5060

  • KDE Plasma

  • Wayland (also tested X11)

  • Multiple HDMI monitors using HDMI-to-DisplayPort adapters connected to GPU

Problem:

  • One or more monitors lock to very low resolution (640x480 or similar)

  • KDE display settings do not show proper native resolutions

  • xrandr/modeline attempts fail

  • Sometimes monitor reports “-hsync”

  • Main monitor may work correctly while secondary monitors fail detection

Important detail:
These exact same monitors + adapters work correctly in Pop!_OS on the same hardware.

Things I already tested:

  • Rebooting with only one monitor attached

  • Different adapters

  • Wayland and X11

  • Power cycling monitors to reset EDID

  • Fresh CachyOS install

  • NVIDIA drivers included with CachyOS

  • Different ports on GPU

Question:
Has anyone seen EDID/handshake issues specifically with HDMI-to-DP adapters on CachyOS/KDE/NVIDIA?

I’m trying to determine whether this is:

  • KDE/Wayland related

  • NVIDIA driver related

  • Kernel related

  • Adapter compatibility issue

  • EDID parsing issue

Any ideas would be appreciated.