No signal or broken resolution after monitor powers off / switching inputs

I’ve been having this issue for quite a long time now across multiple machines, multiple NVIDIA GPUs, multiple driver versions, multiple monitors, and multiple versions of Ubuntu LTS. Below describes my current setup and the issue that I constantly face:

I have two computers, a workstation, and a desktop. Both computers have an NVIDIA GPU. I use a USB hub to use the same keyboard for both computers. My MX Master 3 mouse has the ability to connect to up to 3 devices over bluetooth, so that’s how I use the same mouse between the two machines. Both computers are connected to the same monitor (Samsung Odyssey G95NC 57"), the workstation is connected via DisplayPort on the monitor, and the desktop is connected to HDMI on the monitor.

When I want to switch between computers, I lock one computer, press the button on the USB hub to switch the keyboard, and then manually change the monitor to either DisplayPort for the workstation, or HDMI for the desktop. The problem I am facing is that a majority of the time when I switch over to HDMI on the desktop, the monitor remains blank. I can use Ctrl+Alt F1 to switch to a TTY, but the default TTY (F2 or F7) will often not show up. In the times when I can get the GUI to show back up, the original resolution (7680x2160 @ 120Hz) is no longer available. This issue also occurs if I turn the monitor’s power off and then turn the monitor back on.

I’ve tried multiple HDMI cables. The one I am currently using is a “Zeskit Maya 2.1 8K HDMI Cable 6.5ft 4K120Hz 48Gbps for eARC Soundbar Ethernet Gaming 144Hz Certified Ultra High Speed HDR VRR HDCP 2.2 2.3” (https://www.amazon.com/gp/product/B07S1CGQ9Z/).

If it matters, I’m using i3wm, and i3lock to lock the screen.

Please let me know what information would be helpful for you to diagnose and identify the root cause.

Attached is the output of nvidia-bug-report.sh:

nvidia-bug-report.log.gz (491.9 KB)

For anyone that finds this thread in the future and has the same problem, I’ve found a workaround. I’m now using:

$ xset dpms 0 0 0

To prevent my monitor from going to sleep. This way signal is never lost so the screen never goes blank and can’t come back.

If nvidia gets back to me with a solution, I’ll update this post.