Front panel has no "headphone detect" wire; is there another option?

Question

I'm in the process of building a new PC. The motherboard is an MSI Tomahawk B450. Its front panel audio connector has three pins related to headphones; they're labelled "Head Phone R", "Head Phone L", and "Head Phone Detection".

Well, my (older) case's front panel has wires for headphone L and R (which I connected to the proper pins), but there isn't one for headphone detect. Unsurprisingly, Windows/Realtek never detect headphones in the jack and I never hear any sound. I tried disabling headphone detection in Realtek software hoping that would just leave the jack active all the time, but this didn't make any difference.

I'm assuming the problem is because I don't have a wire to connect to the headphone detect pin, but I could be wrong about that. But if I'm not, is there any workaround, or am I stuck?

The rear speaker port works fine.

Answer 1

After doing some more research, I can now phrase the question more precisely: my case's front panel audio header is for AC97, but my motherboard's connector is for HD Audio. With those terms in my vocabulary, Google and stackexchange both had a lot of suggestions to offer. The standard advice is to wire up the connectors you have to the pins with the corresponding names, and leave the others open (which I'd already done). Then you need to go into your audio driver software (Realtek in my case) and disable front panel headphone detection (because the hardware can't do it) and enable duplicating the audio stream to both the front and rear ports simultaneously (ordinarily the driver mutes the back port when headphones are detected in front, but since we can't detect them, we need to disable that).

I'd done all that already and it still didn't work. But there's another setting in my Realtek software that maybe didn't exist when the other answers were written: "Disable front panel popup dialog." I'm not sure why that makes any difference here, but once I checked that box, the headphones started appearing as a second output device and worked fine (in fact, experiment shows that this was the only setting I truly needed to change).

Of course, I need to manually switch the Windows playback device to headphones after plugging them in since it's not possible for the hardware to detect that I've done so, but that's ok.