UPDATE! My monitor has an HDMI 2.1 port and a display port 1.4
My goal of achieving 4K@240Hz on Linux initially led me to select HDMI 2.1, assuming its superior native bandwidth was essential, especially since I knew DisplayPort 1.4’s bandwidth is insufficient for 4k 240hz. Crucially, I didn’t fully understand at the time how my GPU’s DisplayPort 1.4a output, by utilizing Display Stream Compression (DSC), could enable the monitor’s standard DP 1.4 that otherwise cannot drive this resolution at that refresh rate, to effectively meet these demands; this incomplete understanding made DisplayPort seem like an unworkable option and cemented my focus on HDMI 2.1. Consequently, I spent days troubleshooting what I believed were software issues, convinced my physical interface choice was already optimal. The surprising and immediate success upon eventually switching to DisplayPort highlighted that the NVIDIA Linux driver’s DSC implementation via the GPU’s 1.4a port was, in fact, more stable for my specific configuration than its HDMI 2.1 Fixed Rate Link handling. I accept that this was my mistake in prematurely dismissing the DisplayPort pathway due to a premature assumption of DP capabilities and lack of understanding about DSC over DP 1.4 via 1.4(a) port located on the GPU.
This experience suggests that for my particular hardware combination, the NVIDIA Linux driver’s handling of DisplayPort 1.4a with DSC for 4K@240Hz is currently more stable or effective than its implementation of HDMI 2.1 Fixed Rate Link (FRL) for the same demanding specifications. It might be beneficial for the NVIDIA team to investigate potential issues, limitations, or compatibility quirks with HDMI 2.1 FRL at very high bandwidths on Linux, particularly with certain displays, as DisplayPort with DSC provided a flawless experience in this instance where HDMI 2.1 did not.
I hope this detailed account of the problem and its resolution helps other users who might be encountering similar difficulties and provides useful data for the team(s) at Nvidia.
I (was) experiencing severe and unusable display artifacting (looks like full-screen static) when trying to run my 4K monitor at its 240Hz refresh rate over HDMI on Linux. This monitor is a dual mode panel and a physical button can swap it from 4k 240hz to 1080p 480hz. The issue also occurs at the 1080p 480hz mode. I’m hoping to get some assistance in diagnosing and resolving this.
Here is an unlisted video showing what I am referring to: https://youtu.be/rMv57ZJtyqI
The exact same hardware setup (monitor, HDMI 2.1 cable, GPU) works flawlessly at 3840x2160 @ 240Hz & 1080p 480hz in Windows 11.
On Linux, the monitor works at 3840x2160 @ 144Hz. The artifacting issue is specific to the 240Hz and 480hz modes.
System Information:
GPU: NVIDIA GeForce RTX 3090 Ti
Monitor: LG Ultragear 32GS95UE-B
I also am running a second monitor, 1440p @165hz over displayport, no issues.
Connection: HDMI (using a certified Ultra High Speed HDMI 2.1 cable confirmed to work at 4K@240Hz and 1080p 480hz, same gpu, in Windows
NVIDIA Driver Version: 570.144 (CUDA Version: 12.8) - Confirmed via nvidia-smi
Operating System: EndeavourOS
Kernel Version: [ 6.14.6-arch-1-1
Desktop Environment: KDE Plasma (issue occurs in both Wayland and X11 sessions), tried GNOME and the issue still exists.
When attempting to set the display mode to 3840x2160 @ 240Hz on my primary HDMI-connected monitor, the display becomes entirely filled with unusable artifacts/static. The system remains responsive.
Troubleshooting Steps Performed (Problem Persists):
Confirmed Stability at Lower Refresh Rate: 3840x2160 @ 144Hz is stable on Linux (both Wayland and X11).
Tested in KDE Wayland Session:
HDR Disabled: Artifacting at 240Hz persists.
VRR Settings Varied: Tried “Always”, “Automatic”, and “Disabled” for VRR. Artifacting at 240Hz persists regardless of VRR setting (with HDR also off).
Scaling Factor: The issue occurs regardless of desktop scaling factor (tested with 1.5x and 1x scaling).
Tested in X11 Session (Plasma on X11):
Logged out of Wayland and into an X11 session.
Attempted to set 3840x2160 @ 240Hz
The same severe artifacting/static issue occurs in X11, identical to the Wayland session. This suggests the issue is not specific to the Wayland compositor.
HDMI Cable: Using the same high-quality HDMI 2.1 cable that successfully runs 4K@240Hz in Windows.
Output of the nvidia debug logs attached, one with the monitor on the working setup and one with it actively artifacting.
Is this a known issue with the NVIDIA 570.144 (or recent) Linux drivers for 4K @ 240Hz over HDMI on certain displays/configurations? I did attempt installing my drivers using the .run script on Nvidia’s site for Linux X64, installing using the nvidia-inst package, the nvidia-open and the ‘nvidia’ package, always from fresh EndeavourOS each time to be safe. Same issues. I also did a downgrade from 570.144 to 570.133 and it still occurs. This doesnt happen on Nouveau, because it wont let me go 4k 240 on Nouveau. ALSO using the 575.51.02 open beta DKMS, same issues.
Are there any specific nvidia-settings, kernel parameters, or other configurations I should try to potentially resolve this artifacting?
What further diagnostic information would be most helpful for NVIDIA to investigate this?
Any assistance or insights would be deeply appreciated. This is my primary display, and I’m keen to get it working at its full capability on Linux as it does in Windows.
nvidia-bug-report.log.gz (1.4 MB)
nvidia-bug-report.log (4k 144).gz (1.5 MB)
tried the latest Pop!_OS 22.04 LTS with NVIDIA which states Computers with 16 series NVIDIA Graphics or newer (e.g. GTX 16xx to RTX 5xxx) I booted off this USB install, and this comes with Nvidia drivers loaded already just in the live USB environment. In this environment I could still reproduce the issue, without even having touched anything. Literally booting from the ISO and changing Display refresh rate. It didn’t do it right away, but it did do it. No other apps were open or installed by me.
Thank you for your time and help.