No video when dvi_mode=0

[emiliom]

I built a MiSTer Multisystem recently and after a few initial problems everything seemed to be working ok. I had the MMS and my PC connected to the same monitor, PC via DVI and MMS through VGA. So no problems, I just switched between the 2 inputs direct from my monitor and had a really, really cheap 2 device KVM switch managing the keyboard and mouse and everything was fine. I just had the mild annoyance of having to unplug / plug my headphones between the PC and MMS when switching systems.

As I'm going to add a 3rd system to my setup shortly I decided to upgrade the KVM switch to a 4 input device version with audio and get rid of the headphone hassle. And that's when I hit my problem. I get no audio from the MMS through the KVM switch. Everything PC side works as it should, but if I have dvi_mode=1 set I get a HDMI picture but no sound, which of course you wouldn't as dvi mode doesn't deliver sound via the HDMI. The confusing part is when I set dvi_mode=0 I get no HDMI picture at all. Not only that, but as I still have the VGA cable connected and switch to VGA on my monitor, I do have a picture, but I still have no sound. So it seems like if I set dvi_mode=0 I get nothing at all down the HDMI cable...no picture and no sound.

It has occurred to me that it could be a hardware fault with my Multisystem but before I start messing with the HDMI connector I thought I'd better check if there was perhaps a simpler problem to do with ini settings that I'm missing? And if it is a hardware fault, why would it output an image when dvi_mode is set to 1, but not zero?

[aberu]

Yeah that is not expected. dvi_mode being enabled only makes it so audio is not transmitted over HDMI, that's it. It really shouldn't impact hdmi video when turned off at all.

Can you post your whole MiSTer.ini here in case there are other anomalies?

[emiliom]

Sure. Here you go.

MiSTer.ini

(13.98 KiB) Downloaded 195 times

Other than the vga_scaler being turned on to get the VGA output working and setting the video mode to my monitor's native resolution I don't think I changed much more.

[aberu]

Try this one for me:

MiSTer.ini

(16.65 KiB) Downloaded 233 times

[emiliom]

Same...still no HDMI picture and no sound.

I ran an update on the MiSTer as well just in case but still no joy. I'm struggling to think it could be anything other than a fault with my HDMI connector, but I really don't get why I get no HDMI picture just by setting dvi_mode=0.

[emiliom]

Well, I jiggled my HDMI cable about a bit and noticed I was getting red spots on the screen so I thought definitely a problem with the HDMI connector. So I de-soldered it then re-soldered it, but no change. Then I disconnected the HDMI bridge between the Multsystem and the DE-10 and directly connected the DE-10 HDMI output to the KVM switch and still the same problem. So it's definitely not the HDMI connection on my Multisystem. I also tried 3 different HDMI cables and that didn't work either.

So only thing I'm left with is that it won't work through the KVM switch, but I don't see why that would be.

[emiliom]

I tried a different KVM switch and that sort of worked. Now I have video and audio from my MMS, but no sound from my PC. Go figure.

[mist-rich]

I did think the likely culprit could be the KVM switch when reading that.

I have a similar setup although use optical for the sound into a DAC which has a source select button so I can switch between Mister & PC. Also use a HDMI switcher (just behind) for another device. If I want switch between monitor speakers & headphones on PC, rather then going through the Windows Audio output settings I assigned a button to a StreamDeck to switch between the 2.

Is the audio source in sound/volume settings on your PC definitely set correctly? If so, it must be that KVM.

PXL-20230803-194346806-2.jpg (435.03 KiB) Viewed 3579 times

[emiliom]

Is the audio source in sound/volume settings on your PC definitely set correctly? If so, it must be that KVM.

Yes and no, and I think this is where the problem lies with my 'current' switch. I have 2 audio devices listed in Device Manager (or the Realtek Audio Manager), but they're both digital outs. If I look on the Realtek Manager my only highlighted out is the Optical out (bottom right), so I don't think it can output to the 3.5mm analog out because it can't seem to see it.

Audio.jpg (112.23 KiB) Viewed 6761 times

On the switch I tried before where my PC sound was working I had one extra sound device. I can't remember what it was called exactly but it was some generic USB sound device, and the Front audio out (bottom left) was then highlighted and selectable, and chosen by default. But on that KVM the sound didn't work with my MMS. So this current KMV switch may work if I can use the digital out. Problem is I just want to plug a set of headphones into it so I'd either need a DAC if the sound is making it's way out of the Optical out, or just use a 3.5mm audio switch / mixer to manage the sound. I guess the DAC would be neater as it's one cable from the switch to the DAC and then the headphones from the DAC. There's one on Amazon for £22 so it's not expensive, it's just I'm paying for something I really shouldn't need. Either way it seems I'm looking at 2 boxes because I can't seem to find a KMV switch where everything works properly.

It occurs to me the switch may need a firmware or driver update as the instructions said something about plugging it into the PC and it would automatically load the driver. But I didn't notice anything when I plugged it in - it didn't seem to install a driver. I've contacted support but I'm still waiting for a response. If I don't get any joy there I think I'll just have to choose the 2 box solution.

[mist-rich]

Understandable and you're right, it should work - it's not as if you're asking for something hugely complex from it
Hopefully a firmware update will fix.

[emiliom]

I don't think I'm going to get very far with this. Tech support have been less than helpful, mainly because their English is very limited. Either that or they're just lazy. I did get another switch exactly the same (great thing about Amazon, you can just send everything back), plugged it in via the firmware update port first to see if it installed a driver, but it was nothing new. Turns out it's the same driver the other one was already using. So I did try swapping them over but there was no change.

I did get contacted by tech support for the previous switch, and they were a lot more helpful. Also a Chinese company but their English was perfect and they gave me decent instructions and a number of things to try. One thing I hadn't remembered to try was directly connecting the DE-10 to my monitor via HDMI, and what do you know...I got exactly the same problem I had originally. If dvi_mode=1 I get a picture, but with dvi_mode=0, no picture. So that first switch appears to be replicating exactly what happens when the DE-10 is connected to the monitor. That's even more confusing because it begs the question why does the DE-10 output work with the second KVM switch with dvi_mode=0 set, when it doesn't even work when directly connected to the monitor with dvi_mode=0 set?
I also have a VGA->HDMI adapter (with 3.5mm audio input), and if I use that to connect the MMS I STILL get no video / audio out of the first switch, even though I do get VGA output direct to the monitor and audio out direct from the 3.5mm audio out.

The only conclusion I can come up with is that the first switch just doesn't like audio from the DE-10. It can only handle video from it and nothing else. Because even if the combined audio / video signal was messing up my monitor, the switch should still output the audio to the 3.5mm out and it doesn't even manage that.
With the 2nd switch, maybe it's just not compatible with the audio hardware I have on my PC? Mind you, I thought Realtek was pretty common so it's a bit odd.

I think I'm going to keep the first switch as it seemed more reliable in use and just go with a small mixer with 3.5mm inputs to handle the audio. At least that way I can listen to music from my PC if I want while coding in a core, and when I'm playing games I can also turn up the volume as some of the arcade cores are rather quiet.