Reply 40 of 51, by LSS10999
Stainlesscat wrote on 2021-03-24, 16:31:My presented topic was about the presence of compatible LPC to PCI bridges to get Sound Blaster ISA resources (ISA I/O port resources not DMA!) in order to get working emulation of sound blaster ports to work because ICH7 and later only support ISA style port resources with legacy ports decoding through PCI with conjunction by a compatible LPC bridge connected to ICH chipset, The chipsets cannot handle ISA resources alone which is why all of them have an LPC Bus present with an LPC bridge connected. I am not referring to chipset exclusive features support like D-DMA or PC-PCI! as others stated already that ICH5 was bottom of the road... D-DMA is an ISA DMA resource exclusive to certain chipsets that supported it and i'm well aware Intel's I/O Controller Hub never supported this.
And Just if there is confusion about what i'm talking about let me be clear... I'm only referencing chipsets like ICH7 through 10 as those chipsets do have Legacy ISA through PCI resources but not ISA DMA resources (ISA I/O ports only). And again i'm not refering to exclusive support like PC-PCI (SB-LINK). Also note LPC to ISA bridges are only important actual ISA devices which my topic was not about. Mines was about LPC to PCI chipsets which does give ISA resources (Again no DMA) through PCI which is needed for SOUND BLASTER PORT RANGE FOR SOUND BLASTER EMULATION!
The whole reason i wrote my previous posts because i found out that sound cards that use Sound Blaster TSR driver emulation can still not work without the previously aforementioned requirements.
Okay, sorry about the misunderstanding. It seems some boards in that range (like yours) have trouble getting even basic stuffs (excluding DMA) to work.
IMO the Winbond chip (maybe ITE, sometimes Fintek) that I can always find on a motherboard is a Super I/O. Just took a look at W83627HF (which is one of the common ones) and it does also appear to provide a complete LPC interface along with other stuffs (PS/2, COM, LPT, etc.), so you're right about the LPC bridge thing.
It's just that I don't have a clear connection between PCI sound card's legacy emulation and the chipset's LPC interface yet. I tried looking for one, but nothing looked clear to me as some motherboards exhibit similar behaviors for a given sound card, while they gave me completely contradictory information (maybe DMI is not the right place to look for certain details).
Don't know which chip the board you're having problems with uses, though. If the board is using the same chip as others (not crippled ones) then it's possible the BIOS might have disabled some functionalities that the board is not actually using (or maybe not wired at all). After all, OEM boards tend to lock down a lot of stuffs, which I think is to ensure users don't accidentally void their warranty.
On the other hand, IRQ handling can be problematic with modern motherboards. I recall having a very hard fight getting it right on new VIA chipsets. PCI audio cards in question would not work unless I make the card actually take IRQ 5 through trial and error (yeah, sometimes I have to install expansion cards to particular slots and even in a particular order to get it right). Reserving IRQ5 for legacy usually don't work in such cases, but it helped getting ISA sound cards working on older VIA chipsets...