DJNW wrote on 2024-10-14, 12:01:

Okay, so hear me out - the onboard audio of the MX is HD Audio, so it can only be activated via SBEMU, which can cause issues with certain dos extenders (eg TD2192), right?

Nope. Vortex or AMD LX southbridges are not supported by SBEmu.

DJNW wrote on 2024-10-14, 12:01:

Someone could get hold of one of the various V86MX based Little Guys out there (eg ebox3350MX) and (assuming the right pins are accessible on the board) make up and attach a little LPC-attached sound card. If it's doable, it would be both cheaper and faster than having a new SOM shipped from Taiwan, easier to assemble and encourages reuse of old parts.

Cheaper - maybe, but definitely not easier.
You could try through and share the experience.

DJNW wrote on 2024-10-14, 18:49:

Okay, so hear me out - the onboard audio of the MX is HD Audio, so it can only be activated via SBEMU, which can cause issues with certain dos extenders (eg TD2192), right?
Someone could get hold of one of the various V86MX based Little Guys out there (eg ebox3350MX) and (assuming the right pins are accessible on the board) make up and attach a little LPC-attached sound card. If it's doable, it would be both cheaper and faster than having a new SOM shipped from Taiwan, easier to assemble and encourages reuse of old parts.

It's an interesting possibility. Although the LPC soundcard would have to be pretty small to make sense.

I have started porting nukeykt's LPC soundblaster to the ice40 FPGA, maybe that would be a good path - https://github.com/rasteri/LPCBlaster

What's the benefit of LPC soundblaster over LPC2ISA bridge? I can see only tha smaller size but it lost the universality to connect any ISA soundcard you want. And it doesn solve missing LDRQ# anyway...

rasteri wrote on 2024-10-14, 19:31:

It's an interesting possibility. Although the LPC soundcard would have to be pretty small to make sense.
I have started porting nukeykt's LPC soundblaster to the ice40 FPGA, maybe that would be a good path - https://github.com/rasteri/LPCBlaster

Nice, but IMHO, Vortex is not the best candidate for testing.
LPC can really mess things up, including BIOS.
And digging up Vortex integrated flash recovery process still gimes me shivers 0_o

RayeR wrote on 2024-10-14, 21:06:

What's the benefit of LPC soundblaster over LPC2ISA bridge? I can see only tha smaller size but it lost the universality to connect any ISA soundcard you want. And it doesn solve missing LDRQ# anyway...

PC/104 is smaller than any ISA soundcard anyway. Just a possibility of adding a compatible soundcard and keeping original design may be more than enough.
LPC SB could be made as a module, pretty much the same as Vortex SOM, which anyone could then use as a base for a soundcard design for their system (with a "Quest For LDRQ#" included).
Some thin clients have mPCI slot onboard for wifi for example, and a soundcard could be designed around that slot.

I had a similar idea of creating an ISA card, in which you could swap sound chip IC's as modules (highly integrated ones, such as ALS120, ESS1868, CS4237B, etc).

Paul_V wrote on 2024-10-14, 21:40:

LPC can really mess things up, including BIOS.

Indeed. Care must be taken when handling stuffs on LPC bus.

A vanilla dISAppointment v0.1/v0.2 (without the extra resistor) would prevent the system from booting. As for v0.3, I couldn't get it work, and it somehow messed up the SuperIO that the system may not boot and in some cases even prevented fans from spinning up.

AMD chipsets (including later Ryzen CPUs) appear to have some restrictions on LPC access in place, that made dISAppointment only somewhat useful for a debug card (port 80h), but in turn made the board immune to those interferences (e.g. the AMD board will boot without any issue even when dISAppointment v0.1/v0.2 was without the extra resistor required for its proper function).

The nature of AMD's restrictions on LPC were unclear as they were never explicitly mentioned in the documentations I've looked at...

RayeR wrote on 2024-10-14, 21:06:

What's the benefit of LPC soundblaster over LPC2ISA bridge? I can see only tha smaller size but it lost the universality to connect any ISA soundcard you want. And it doesn solve missing LDRQ# anyway...

Yeah mainly just smaller size. Think TPM module with a 3.5mm socket on it...

Also soundcard chips are only available NOS with a finite supply, an FPGA solution would be available indefinitely

But yeah obviously this wouldn't solve LDRQ, or at least not without some ES1938S-TDMA-style shenanigans.