I am getting no sound when using a compiled ac97 audio driver from WDK 8.1's sample code in a Windows 7 (x86)/Windows Server 2003 (x86) VM ran using VirtualBox 6.0.20. I have noticed that there is a CIV is out of range error being mentioned in the debug output shown in WinDbg. I chatted with a developer who told me that its possibly an issue with its MAX_BDL_ENTRIES code. The debug output that I get when changing DBG_DEFAULT to DBG_ALL in the proper line of code found in its debug.h file can be found at https://paste.ee/p/sMMJH.