I am trying to connect to a proxmox host. I should see the host login text scree (as well as boot screens). I am connecting to a HDMI port on my Nvdia GEFORCE. This worked fine with a AVaccess KVM, and with a variety of monitors.
However, when I connect to the Comet, I get told there is no HDMI signal.
I never get any screens including rebooting the host.
I have tried the following things:
It worked when connected to a AMD Radeon card based VM on the same host, it worked.
Changed the EDID to a variety of mode including several at 1024X786 (after I set GRUB_GFXMODE=1024x768 in grub), following the guide in the docs.
I can see the login screen in the other KVM. Keystrokes work.
According to the logs, your graphics card is not outputting any HDMI signal.
Are you sure that in this case, plugging in the monitor will actually display something? Because it's unlikely that the KVM can't read the signal, but the monitor can.
I didn't get it. When you mentioned the GeForce graphics card, I thought your computer was a regular desktop. Then you said you also had an AMD graphics card, so I assumed it was a desktop running a virtualization system with multiple GPUs passed through. But then you used a Type-C to HDMI switch hub meant for laptops. At that point, I was completely confused about what kind of device yours actually is.
Even if the picture on a Type-C hub like AV Access you mentioned is normal, it doesn't necessarily prove that your graphics card output is normal either.
WTF are you talling about? I never said I connected via USB-C. I detailed the other KVMS it work without a problem.
It is a proxmox host, the console comes out of a Nvidia card. If I move the cable from the comet to the AVaccess KVM it shows the screen without any issues.
The keyboard works when connect to the comet, as I can see that in the working KVM (typing crap at login, and hitting returns)(, and I assume I could see failed logins to the proxmox host.
So to recap, this works with other KVMs. Your usb keyboard works when connected to the nvidia console, and you cannot see HDMI on it.
Is this a bad unit, or failed product? If I need to get my money back and try a different solution I will.
Sorry about the earlier confusion with your setup. You made it perfectly clear you're going straight HDMI from the RTX 4070 Super, no USB-C hubs or adapters involved.
I know you already tried modifying GRUB_GFXMODE earlier, but the key here is adding nomodeset to stop the Nvidia kernel driver from dropping the HDMI signal during console boot.
You can try updating the Proxmox VE parameters like this:
Edit your GRUB configuration file:
nano /etc/default/grub
Update the default command line options to include gfxpayload=text nomodeset.
Uncomment the line GRUB_GFXMODE by removing the # and set the desired resolution, such as 1024x768.
GRUB_GFXMODE=1024x768
Enter the command below to apply the configuration
update-grub
(Note: If you also pass through the GPU to a GUI/desktop VM, you can ensure proper scaling by setting the GPU scaling mode to "No scaling" in the Nvidia settings panel: Nvidia Display Scaling Help)
