Reply 100 of 130, by Doomn00b
Modern AMD chipsets are a complete no-go for PCI audio cards. I once had boards of each generation (700/800/900) and none worked […]wrote:
I have a question here... I have a Asus M3A78-CM rev 1.01G motherboard in my possession, it's an AMD board, it features an SB700 […]
I have a question here... I have a Asus M3A78-CM rev 1.01G motherboard in my possession, it's an AMD board, it features an SB700 southbridge chip - just to make sure, I had a look at the specs, and unless I've misunderstood it, this Southbridge has very complex DMA support, with Midi and Adlib mentioned:
Is it me, or can this MB use PCI soundcards which will work quite well in pure dos??
Here's the specs for the entire board:
http://static.highspeedbackbone.net/pdf/Asus% … rd%20Manual.pdf
AMD rarely gets mentioned in these threads, so perhaps it's a good idea to take a closer look at their chipsets. A common thing I keep hearing, is that AMD has terrible support for ISA and DOS PCI sound, but as Ruthan says... "there are many urban legends spouted".
Some of the urban legends are indeed true... the SB700 line of southbridge chips are all good, but later chipsets have various types of DEFECTIVE LPC controllers - so, SB750S is the last one to definitively have a functional and rich LPC - complete with advanced Super-I/O.
Modern AMD chipsets are a complete no-go for PCI audio cards. I once had boards of each generation (700/800/900) and none worked, not to mention on those chipsets, the games still can't detect sound blaster even after I loaded the TSR (and confirmed the TSR is indeed loaded).
EDIT: I briefed the datasheet a bit and did find references of legacy audio. It seems starting from pages 171 (SMBus Module and ACPI Block) there were references about enabling some legacy audio hardware I/O addresses (Adlib 388-389, MIDI 300-330, Sound Blaster 220-280, WSS 530/604/E80/F40) to trigger SMI# (System Management Mode).
This makes it possible on SB7xx to emulate legacy audio using system management mode hacks, but it doesn't provide any means to make existing hardware's legacy TSRs usable (as they don't and can't use SMI). One needs to develop specific SMM code against the chipset and the target sound card then integrate it to the BIOS to get legacy audio working. For this, it might be more practical to target the onboard audio than targeting a specific discrete audio card (as if targeting a discrete card you'll probably need to modify the BIOS code every time you change stuffs, unless if it's possible to put soundcard-specific code in a higher ring from SMM(ring -2)). I'm not an expert in SMM so I'm not entirely sure). Again, this is only a possibility.
EDIT 2: Did not find any similar references on SB8xx register reference guide (and there's no SB9xx databook out yet), but on SB8xx databook it has references about LPC (which isn't useful on its own, SB7xx also has such mentions). The audio-related SMI# stuffs are so far only mentioned on SB7xx chipset documents.
PS: It has been possible to use SMI# to emulate legacy audio and other stuffs before (see Virtual Subsystem Architecture (VSA)).
EXCELLENT find, my dude!
So, there might be a form of virtualization available for legacy devices, eh? We just have to figure out more about it, 🤣! Custom Bios's are a thing, so once we know more, we shalt not let that stop us.
In the meantime, I've been checking out various AMD 790FX and 790GX bords, and a few look quite promising! One actually has 7 slots, and would hence be suitable - I believe it takes at least one AM3+ cpu as well...
DFI DK 790FXB-M3H5