Isn't the IT8888 configured in some transparent mode where it masks itself like intel PCI2ISA bridge? Look at full PCI devices listing if you find some...

hpxca wrote on Yesterday, 23:24:

Edit: I guess it's because it's the older ITE8888F instead of the newer ITE8888G. Might still work since as best I can tell they are very similar, but the current program doesn't recognize it.

The F and G variants appear to be the same chip with a different package, so there is likely something else stopping it from working

Yeah, it's somehow hidden or lying. I tried PCICFG and pcisleep under DOS. Both list everything you'd expect including the usb controller and Ethernet controllers (when they're enabled). But the IT8888F isn't listed. There is however an Intel PCI to ISA bridge listed. So if that's not actually the chipset then that must be it.

hpxca wrote on Today, 04:14:

Yeah, it's somehow hidden or lying. I tried PCICFG and pcisleep under DOS. Both list everything you'd expect including the usb controller and Ethernet controllers (when they're enabled). But the IT8888F isn't listed. There is however an Intel PCI to ISA bridge listed. So if that's not actually the chipset then that must be it.

The Intel PCI to ISA bridge would be the the LPC interface on the ICH4 southbridge which is used to connect to the Winbond Super I/O chip

So my knowledge of how PCI works is pretty limited, but the AI has been teaching me a lot. Digging through the datasheet of the IT8888F I can't find anything that suggests it can hide itself intentionally, like a setting in a configuration register or a strapping resistor. It does support subtractive decode though and I think that's probably what's going on here. Given this is an ICH4 southbridge I kind of expected DMA to just work and as @KYA mentioned in the original post the ICH4 supports PPDMA so why wouldn't it just use that? I wondering if maybe the BIOS just isn't configuring it properly? The chip supports configuration via an external serial EEPROM as well, but I see no such EEPROM anywhere on the board around the chip so I assume that the BIOS is setting up the registers at boot. I even dumped the BIOS of this board and put it into modbin6 to see if there was something hidden in there that might be related to it, but nothing stood out. I can't find any other versions of the BIOS for this board anywhere.

With some AI help I might try a few things to play with the configuration registers and see if I can somehow "turn on" PPDMA? But i'm not sure I can make it appear on the BUS so that KYAs program can find it, though I may be able to write something that can detect it anyway...

hpxca wrote on Today, 04:14:

Yeah, it's somehow hidden or lying.

ICH settings usually hide PCI-ISA bridge (IT8888) to avoid conflicts.
You need to search ICH datasheet for something like this.

Ah yes, it should be like this. So to check and clear bit 24. But it seems also this feature is depending on HW configuration - if Ad22 line is routed to ITE as described...