If your multifunction audio device contains game ports, note that the adapter driver's handling of the game ports on Windows 2000 and later differs from that on Windows Me/98. In contrast, all three operating systems are consistent in their use of WDM audio drivers. On Windows Me/98, the joystick portion of the operating system is still VxD-based and you must write a hybrid VxD-WDM adapter driver. This is unnecessary on Windows 2000 and later, which support joysticks with a DirectInput HID driver.
If your game port requires Type-F DMA transfers, note that these are supported on Windows Me/98, but not on Windows 2000 and later. The PC 2001 System Design Guide does not require support for legacy game ports on new PCs, which are likely to use USB joystick devices instead.
A limitation in Windows 98 prevents loading a child VxD from a WDM parent. The inability to load the VxD can cause problems with a multifunction device that combines a joystick, which requires a VxD on Windows 98, with an audio device that has a WDM parent. This limitation has been removed in Windows 98 SE and Windows Me.