External Display Not Working - NVIDIA RTX 4060 Mobile + Hybrid Graphics (Works in Windows)
System Information
- Laptop: Lenovo LOQ 16APH8 (Model: 82XU)
- Operating System: CachyOS Linux
- Kernel: 6.18.1-2-cachyos (also tested on 6.12.62-2-cachyos-lts)
- Desktop Environment: KDE Plasma 6.5.4 on Wayland
- GPU Mode: Hybrid (via supergfxd)
Hardware
- iGPU: AMD Radeon 780M Graphics (Phoenix1) - PCI 06:00.0
- dGPU: NVIDIA GeForce RTX 4060 Max-Q / Mobile (AD107M) - PCI 01:00.0
- Internal Display: 1920x1200 @ 144Hz (connected to AMD GPU, works perfectly)
- External Monitor: GBT AORUS FO32U2 (connected via HDMI to NVIDIA GPU)
NVIDIA Driver
- Driver: nvidia-580xx-dkms 580.119.02-1 (proprietary)
- Utils: nvidia-580xx-utils 580.119.02-1
The Problem
External displays connected to the NVIDIA GPU are not detected at all. The monitor shows it’s receiving a signal and says “connected” but displays nothing. The laptop does not detect the external display in KDE Display Settings or any other tool.
Important: The NVIDIA GPU itself works fine - gaming works perfectly (confirmed via nvtop and Lutris showing GPU usage). The issue is specifically with display output, not general GPU functionality.
Critical Information
-
Works Perfectly in Windows: The exact same hardware works flawlessly in Windows 11 (on a completely separate drive). External displays work immediately in Windows, confirming this is NOT a hardware issue.
-
Worked on Arch Linux Previously: This laptop ran Arch Linux in the past and external displays worked without issues. This suggests the problem may be CachyOS-specific or related to recent driver/kernel changes.
-
Worked Once Last Week on CachyOS: External display randomly worked one time last week, then stopped working again. Unknown what was different that time - it seemed completely random.
-
GPU Works for Gaming: The NVIDIA GPU functions perfectly for gaming (confirmed via nvtop and Lutris). CUDA/compute workloads work fine. Only display output is broken.
Current Status
nvidia-smi Output
+-----------------------------------------------------------------------------------------+
| NVIDIA-SMI 580.119.02 Driver Version: 580.119.02 CUDA Version: 13.0 |
+-----------------------------------------+------------------------+----------------------+
| GPU Name Persistence-M | Bus-Id Disp.A | Volatile Uncorr. ECC |
| Fan Temp Perf Pwr:Usage/Cap | Memory-Usage | GPU-Util Compute M. |
| | | MIG M. |
|=========================================+========================+======================|
| 0 NVIDIA GeForce RTX 4060 ... Off | 00000000:01:00.0 N/A | N/A |
|ERR! ERR! ERR! N/A / N/A | 2MiB / 8188MiB | N/A Default |
| | | ERR! |
+-----------------------------------------+------------------------+----------------------+
Key issue: Disp.A: N/A and ERR! ERR! ERR! everywhere - the GPU display subsystem is not initializing properly.
However: The GPU itself works fine for gaming and compute tasks. This is purely a display output initialization problem.
Display Detection
All NVIDIA outputs show “disconnected” even with monitor physically connected and powered on. The system doesn’t see the external display at all.
Kernel Errors (from dmesg/journalctl)
During boot, these errors appear:
nvidia-modeset: ERROR: GPU:0: Failure reading DP dongle info for display device GBT AORUS FO32U2 (HDMI-0).
nvidia-modeset: ERROR: GPU:0: Failed to query VR headset for GBT AORUS FO32U2 (HDMI-0)
nvidia-modeset: ERROR: GPU:0: Failed detecting connected display devices
nvidia-modeset: ERROR: GPU:0: Failure reading maximum pixel clock value for display device HDMI-0.
nvidia 0000:01:00.0: [drm] Cannot find any crtc or sizes
Critical error from nvidia-powerd:
nvidia-powerd: CRITICAL! NvRm failed with error Unknown Error and RM Error Code 98
The driver can see the monitor (it identifies it as “GBT AORUS FO32U2 (HDMI-0)”) but fails when trying to read EDID data or initialize the display.
Current Configuration
- GPU Mode: Hybrid (using supergfxd)
- Kernel: Using
nvidia-drm.modeset=1parameter - Driver Settings: Tried various power management and I2C settings (none helped)
What I’ve Tried (All Failed)
- ✗ Switched between proprietary and open-source NVIDIA drivers - same issue
- ✗ Disabled NVIDIA power management options
- ✗ Tried different GPU modes (Hybrid, Vfio)
- ✗ Disabled suspend/hibernate services
- ✗ Tested on multiple kernel versions (6.18.1 and 6.12.62-lts)
- ✗ Different cables and monitor ports
- ✗ Various kernel parameters and driver settings
- ✗ Enabling NVIDIA-only mode in BIOS - System won’t boot past initial boot sequence (can’t even get to TTY)
Questions
-
Has anyone gotten external displays working on Lenovo LOQ 16APH8 (or similar AMD+NVIDIA hybrid laptops) on CachyOS?
-
What changed between Arch and CachyOS? It worked fine on Arch but not CachyOS.
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Why did it work once randomly last week? What could trigger it to work one time but not others?
-
Why does gaming work but display output doesn’t? The GPU runs games fine, but won’t output to external displays.
-
Is there a way to force the display to reinitialize? Some command or service restart that might trigger detection?
Additional Context
- Internal display works perfectly at 144Hz
- Windows 11 is on a completely separate physical drive - external displays work perfectly there
- This worked fine on Arch Linux previously on this same laptop
- External display worked once randomly last week on CachyOS, then stopped working
- GPU works perfectly for gaming - I can game with full GPU utilization (confirmed in nvtop and Lutris)
- BIOS NVIDIA-only mode causes boot failure - system won’t boot past initial sequence if I disable iGPU in BIOS
- The monitor works with other devices and in Windows
- Only issue is display detection - GPU itself works fine for gaming
Can Provide More Info
I can provide any logs or run diagnostic commands if needed - just let me know what would help!
Help Needed
I’m completely stuck. The hardware works (Windows proves it, Arch Linux worked, gaming works). The GPU itself functions perfectly - it’s only the display output subsystem that’s failing to initialize.
The fact that it worked randomly once last week suggests this might be a race condition, timing issue, or some specific state that occasionally gets hit correctly.
Any suggestions, similar experiences, or pointers to documentation would be greatly appreciated!
My Guess
Since it worked on Arch and works randomly sometimes, I’m guessing:
- Maybe something loads in a different order on CachyOS?
- Or there’s a timing issue during boot?
- Or some CachyOS-specific configuration that conflicts with NVIDIA display output?
Not sure - just trying to make sense of why it would work everywhere else but not here consistently.
TL;DR: NVIDIA RTX 4060 Mobile external displays work in Windows but not Linux. GPU shows “ERR! ERR! ERR!” in nvidia-smi. Driver detects monitor but fails with “Error Code 98” when trying to initialize. Hybrid graphics laptop (AMD iGPU + NVIDIA dGPU).
