VGA to HDMI Adapter/Converter

[magic144]

Hi,

 

I have an older original Limetech MD-1510/LI tower (VGA - IGP - output only) - and I recently upgraded my monitor but it doesn't have a VGA input.

I don't normally use the VGA output of my tower, BUT on the rare occasion where console debugging is required, I like to have that facility available.

I recently got a VGA to HDMI adapter/converter (has VGA input + powered via micro-USB, with HDMI output) in the hopes of being able to hook up an HDMI cable to my tower as needed.

Unfortunately, I ONLY see the POST screen/text before the output goes blank. I know there IS VGA output there because I dragged an old monitor out of the basement and hooked it up and see the text login prompt.

I also know the VGA adapter is working OK otherwise as I hooked it up to an old laptop with VGA output and it seems to be showing a Windows 7 login screen just fine.

Can it be that the "normal" VGA output (after POST) from the MD-1510/LI is some kind of unsupported VGA mode that the adapter doesn't recognize/play-nicely-with? Is there any way to debug this or somehow adjust the VGA mode that the MD-1510/LI is using?

 

NOTE - as an experiment, I tried booting the tower into the GUI mode instead of the regular console mode - the VGA adapter is working OK in that mode too...

Any advice welcome, thanks.

[magic144]

I found that I can add/change the vga=<x> in the syslinux.cfg
(following this info https://wiki.unraid.net/Boot_Codes)
I got a table of values by booting and hooking up my old VGA monitor and setting vga=ask

By experiment, vga=6 (VGA 80x60 TEXT) mode seems to work, whereas vga=extended (VGA 80x50 TEXT) mode and vga=normal (VGA 80x25 TEXT) mode does not...
Also found that vga=0x318 (VESA 1024x768x32) also seems to work. Gave up playing for now.

It's all quite confusing - not quite sure why some modes work with the VGA-HDMI adapter and some just don't.

Edited February 26, 2022 by magic144
added ref url

[mrtag]

hey @magic144 did you happen to figure out the issue? I got the exact problem wit my unraid server, any other device I tested works fine with the adapter.

[magic144]

yeah, it's what I said above... I guess my MD1510/LI unRAID server (or at least its graphics output) uses a VGA mode by default that doesn't play nicely with the cheap VGA-HDMI adapter I have (apparently not all adapters are created equal, and they don't work with all possible VGA modes)

so the solution was to add/change (e.g.) "vga=6" (and ONLY add that) to the syslinux configuration (kernel boot options)

I don't have it in front of me right now, but it is editable within the web GUI
i.e.:
https://wiki.unraid.net/Articles/Getting_Started#Boot_Mode_Selector_.28Syslinux.29:~:text=clicking on the flash drive on the Main tab within the Management interface and using the Syslinux Configuration section on the resulting dialog.

----

 

to find ALL the available modes (and what the numbers represent) and debug further, you really need to hookup a REAL VGA-input-capable monitor so you can play around with it (set "vga=ask" and get a list of all the supported modes), then it's trial and error back with your HDMI monitor
gory details here:
https://www.kernel.org/doc/Documentation/admin-guide/kernel-parameters.txt

https://www.kernel.org/doc/Documentation/svga.txt

but hopefully "vga=6" will just work for you

Edited February 6, 2023 by magic144
clarification