Hi, if you have a motherboard with VIA VT82c686 southbridge and AC97 and (!) SoundBlaster sound abilities, you might have noticed that it is NOT enough to enable both AC97 and SB16 in the BIOS CMOS setup. Programs act as if SB16 exists (unless you forget to put a SET BLASTER=A220 I5 D1 or similar line into your autoexec), but you will hear nothing.
Reason: For some stupid reason, the BIOS of your computer is missing a small amount of code (less than 32 bytes) to unmute the card at boot time. As a solution, VIA suggests loading a driver called VIAAUDIO.COM ... which is small, but if you do not use Win3.x (real mode not affected) you do not even need that small program to stay in RAM! Note that if you want AdLib / OPL3 music, you must load the software synthesizer (which uses protected mode and is about 40k small) VIAFMTSR.COM as well. You can get that driver at www.viaarena.com on the page for audio drivers for Win... - along with megabytes of other Win32-only drivers in the same file :-(. So I recommend that you hit google and find a place where you can get the file alone, and/or hit your mail and tell VIA that they should put a ZIP of the DOS drivers (far below 100k even with documentation) online on their official page. http://www.coli.uni-sb.de/~eric/stuff/soft/specials/ViaAC97enableDOS.c (meant for DJGPP, but not ready to compile: Add dos.h and some macros like #define outl(port,data) outportl((port),(data)) #define inl(port) inportl(port) ... my excuses for my syntax-laziness / not including the macros, but I do actually think that nobody will want a bloated C program for this anyway! The VIA tool is 0.5k and ViaAC97enableDOS.c explains you how you can do a bare minimum implementation in 10 lines of NASM assembly...) To do the (non-Win3.x) basic initialization stuff: mov al,0x39 ; for "enter Win" 0x19, for "leave Win" 0x29 out 0x80,al mov eax,0x80003d48 ; <--- adjust to YOUR pcisel here! mov dx,0xcf8 out dx,eax mov dx,0xcfc in eax,dx ; in al,dx would be enough and al,0xfe ; same for "leave Win", for "enter Win" or al,1 out dx,eax ; out dx,al would be enough int 0x20 ; exit to DOS Just paste the above code in a file "soundon.asm", get NASM from the http://nasm.sourceforge.net/ site (unless it already came with your FreeDOS) and do "nasm -o soundon.com soundon.asm" to assemble ("compile") the code into a tiny DOS program which you can run from autoexec. The 0x80003d48 value means: "access PCI, bus 0, device 7, functon 5, register 0x48". The ports 0xcf8 and 0xcf8 are index and data for PCI config access. pcisel = (dev<<11) | (bus<<16) | (func<<8) | register | 0x80000000 in other words. Bus 0 is usually PCI-and-onboard-stuff, bus 1 is usually AGP. The devices on each bus can be numbered from 0..31, but you often have less. The function number will be 0 unless 1 chip/board serves several functions. Register 8 is device categorization: If that (32 bit) register >> 16 is equal to 0x0401 then you have an audio device. That register & 0xff00 tells you which interface (does anybody know which number means AC97?)... Note that DOS programs usually do *not* support AC97 sound. VIA has some extra functionality for SoundBlaster compatibility mode on the chip. Still I would like to know the register contents (0, 4, ... 0xfc) for nForce2 AC97, maybe we can figure out something for DOS on that chipset. Easiest way is to use Linux "lspci" or "scanpci" tools with the right command line options, if possible as root. Eric. ------------------------------------------------------- This SF.Net email is sponsored by BEA Weblogic Workshop FREE Java Enterprise J2EE developer tools! Get your free copy of BEA WebLogic Workshop 8.1 today. http://ads.osdn.com/?ad_id=4721&alloc_id=10040&op=click _______________________________________________ Freedos-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/freedos-devel
