I can only offer some background, as I've been through this before, on linux, wrt (intel) HDA audio codecs ....basically, it's the mixer. In linux, one can use modules options (model='xxxx' or a character array to initialize mixer elements correctly)....

The ones I've gotten working seem to treat it as a desktop and not a laptop

Roughly correct, but it's actually worse than that ~ many desktop mainboards (same audio codec but different brands) have differing mixer initializations ...ie; works on an Asus board, doesn't work on a Gigabyte ... even though both mobo's employ the same chipset & audio codec...

With headphones it works perfectly fine so I'm fairly certain the driver is doing what it's supposed to

Yep, driver for the IDT 92HD73C is working fine, just the mixer array is screwed-up .... (trying to get 5.1 surround sound in linux working hits the same small horrorshow trying to get the 5 channels appearing at the right audio port)

AFAIK the windows drivers initialize in similar fashion...ie; the codec driver loads first to enable the mixer, then the mixer params are applied ~ I have no idea where those params are stored in windows (a .inf file or registry entries) ; someone more savvy with windows may be able to steer you right here, as essentially it's just those params that need modifying.

HTH

Actually what you've said here is a lot more useful than you might think. I went into the other driver folders that wouldn't install and compared a few things to the one that did install and I notice there's a bunch of .ini files for various models of these chips. I wonder if taking one from the official Dell install that was provided for it for Vista and putting it in the IDT folder that's part of the actual install on this laptop might solve my problems. Guess there's one way to find out and if worst comes to worst safe mode is a thing for a reason.

Well, with some combination of drivers and ini files I did manage to get it to detect it as a laptop but it didn't change much otherwise, in fact something along the way broke more stuff as the game I've been testing on it started crashing after I did all that. Clearly that's at least part of the issue but there's more going on that's preventing it from working as intended.

Yeah, it'll be the mixer, for sure .... I've had fun getting audio to work in linux, on multiple laptop machines ~ I had a lenovo here once, that exhibited the same problem as you describe ...ie; works at headphone jack, not main speakers. For example here I'd reference something like https://temposemi.com/products/pclaptop-hd/ to find out what I'm up against. In the lenovo case, it was something goofy like the headphone jack sense logic was 'upside down' as it were -- change a 0 to a 1 and it works as expected. You likely stand the best chance, by rolling back to the drivers that only worked in headphones. From there, you know the codec itself is working, and it's just the audio output path that needs changing. The difference between laptop & desktop here, would be the lack of HD_AUDIO/AC97 font panel port (at a guess)...

...I could be wrong, but at a guess with the headphones working setup, it's not actually the driver perse ~ as mentioned, it's more than likely and installed .inf/.ini file or registry key, because coincidences don't happen =)

I just found this thread ~ https://forums.opensuse.org/t/no-sound-idt-hi … n-audio/70852/8 ...*my* gut feeling is it's the same thing -- headphone jack detection

HTH

More than likely that yes, it is the mixer screwing things up. I've now seen three different versions of the mixer in my quest of driver combining (I'm sure installing 10+ versions of a driver is doing wonders on Windows). What I find quite odd is the driver from SDI that gets it to work at all is a Gateway driver apparently. None of the Dell drivers get it working. Even the official driver which I hadn't tried since it was for 64 bit Vista (unsurprisingly) didn't work at first. However once I get the Gateway one installed that gets the audio service running 'good enough'(?) for it to allow me to install one of the Dell drivers. I really need to pin down which one it is so I don't lose track in the 7 or 8 I've tried. Now I just gotta figure out how to translate that Linux fix into Windows..