Hot plug monitor on headless setup not working

TrueNAS General
1

Hi all,

I run TrueNAS Fangtooth on consumer hardware which includes:

  • ASUS PRIME B550M-K
  • MSI Geforce GT 710 (4 x HDMI outputs)

If I boot TrueNAS with a monitor plugged in and turned on everything works fine - I get the post screens, can navigate bios, use the console etc. Works as you would expect.

If I boot without a monitor plugged in (I run the server headless 99% of the time) it also boots no problems and I have a great server I can manage from the web gui.

If I boot the server without a monitor plugged in, and later hot plug a monitor I get no signal.

I bought a HDMI dummy plug thinking the card needed to see a monitor on boot otherwise it wouldn’t load graphics, but when I later remove the dummy plug and plug in a monitor after boot or just plug the monitor into one of the other HDMI slots while the dummy plug is still connected, I get no signal.

What is going on here? Any advice on other things to try?

I would like the ability to manage the server directly when needed in case there is a hang and I need to restart network services etc or to initiate a controlled shut down if I can’t access the gui for some reason. But I don’t want a monitor always plugged in and turned on for what is mostly a headless set up.

I have considered buying a mini 7 inch monitor and keeping that plugged in and tucked away but that seems a bit unnecessary as well (extra power and gear lying around when not needed). I have also considered a network KVM like the NanoKVM (worried about security on that one though) or maybe the PiKVM thing (but it is like $500).

Anyone else run into this issue and have a cheap fix?

Thanks so much.

2

What happens if you have a monitor attached but the monitor not powered on when you boot TrueNAS? Have you tried using the different HDMI ports on that card?

Since you are not on a server motherboard, I am not sure how the different combos may work. Please post your OS version also.

Do you have a SSH session you can try? It may help to know where it thinks the ‘console’ is while troubleshooting.

3

Some GPUs will disable ports at boot that have no monitor attached. A recent Linux upgrade for me on my desktop PC caused a similar problem.

One fix was to use a HDMI to DisplayPort adapter, (my monitor normally uses DisplayPort in for my desktop). Later, I used a special DisplayPort to DisplayPort pass-through dongle that fakes a monitor for the GPU.

I used something like this:

Note that this is not the exact make / model I used. Not sure if I could dig it up, since I bought mine several years ago.

Now is it annoying / silly we have to resort to things like this for simple functionality?
Yes, but it is cheap enough that I did it and simply moved on.

4

Thanks so much for helping.

It doesn’t work if booted with monitor off and later monitor turned on. I have tried all the various combinations of ports (tedious!) and same issue.

I have ssh to the box. What commands should I type to check which console?

I have the latest fangtooth stable installed.

5

Thanks for this. I have tried a similar dummy plug but hdmi and without the pass through. Same issue. Unless having pass through is the trick? But I still don’t want a monitor attached all the time.

Given ZFS is resistant to abrupt power outages, I may need to resort to just hard resetting the server if it becomes unresponsive for some reason. The only reason I need hot plug monitor functionality is for the rare cases where the server crashes and I can’t ssh in to diagnose. Might not be worth the trouble of trying to sort this out for such rare events. Is really annoying though as seems like a silly problem to be having!

Thanks again.

6

Might be more worth looking into making something like this. Just because a board doesn’t have IPMI doesn’t mean you can’t add it :slight_smile:

7

For my desktop, I normally power the monitor off when not in use. After a certain distro update, the desktop’s screen saver no longer appeared to un-screen save, and remained blank. I ended up power cycling and all was fine.

After this problem repeated, multiple times, I tried to find things to stop that action.

  1. First, I tried to disable complete power save in the screen saver / power options. Did not seem to work.
  2. Tried disabling all the BIOS options related to power save, also did not work.
  3. Used a HDMI to DisplayPort adapter, worked most of the time. But, their were times it failed to bring back the display. Not sure why.
  4. Since I had a DisplayPort to DisplayPort pass-through that was supposed to keep the port & GPU active, I tried that, it works 100% of the time now.
  5. I have added “consoleblank=0” to my Linux kernel command line in Grub, (for my Gentoo Linux desktop, not TrueNAS SCALE), but have not bothered yet to check if that will work without the DisplayPort dongle. If it does, I may try and see if rebuilding the kernel with the option builtin will work too.

So, you have options.

Part of the issue is that TrueNAS SCALE, (and Core), are designed as servers. So server boards with IPMI / iLO / IDRAC / BMC / etc… won’t have this problem.

One last note. It is possible that a full power off of my monitor AND desktop will cause the DisplayPort to DisplayPort dongle to loose it’s stored 1080p60. At which time I might have to reboot twice. But, I do have a UPS which can last more than 30 minutes so it should be rare.