Triple Monitor Display Issues

Ask Fedora
1

Looking for a little help to think this through in an attempt to get all three monitors working properly:

Hardware:
Motherboard: ASRock z790 ITX/TB4 with 1 HDMI, 1 DP and two USB-C (AltDP) / TB4 ports
CPU: Intel i5-13500
GPU: None / iGPU for Display
Monitors: 2 x ASUS - HDMI Only, 1 x LG - HDMI and DP
Cables / Adapters: 1 x HDMI > USB-C adapter, 1 x HDMI to DP cable
OS: Fedora 41 (Linux)
DisplayLink: Updated to the Latest
Kernel: 6.13.9-200.fc41.x86_65

When I plug the monitors in as follows, here are the scenarios and outcomes:

Scenario A:
ASUS > HDMI Cable > HDMI Port (No HDMI Signal / Monitor shows in display settings though but no display)
ASUS > HDMI Cable > USB C Adapter > TB4 Port (Works)
LG > DP Cable > DP Port (Works)

Scenario B:
ASUS > HDMI Cable > USB C Adapter > TB4 Port (Works)
ASUS > HDMI to DP Cable > DP Port (Works)
LG > HDMI Cable > HDMI Port (Works)

Why would scenario B work and not scenario A?

2

Welcome to Fedora @vncntem

You might add for control also the resolutions and the frequency you try to use.
As you have a certain bandwidth you can transfer, you might have some restrictions depending on res & freq and cable/type
you are using.

HDMI has different standards. You will not necessarily always get what is declared for the cable/connection while DP is more a standard you can count on.

I see the bottleneck on HDMI > HDMI, try to lower the frequency and or check a other cable. Or the devices simply do have different versions of HDMI where you try to connect them.