In wdm audio driver architecture, the port class driver(portcls.sys) serves as a container for a collection of port drivers, each of which provides support for a different type of audio hardware functions. The adapter driver serves as a container for all miniport drivers associated with a given adapter. The miniport driver implements a function-specific interface for a function on an audio adapter card that resides on a system bus. It is not recognized as a driver by the operating system. The adapter driver is recognized as a driver by the operating system and is contained in its own .sys file. The adapter driver binds its miniport driver for a particular function to the corresponding port driver for a function type. A port/miniport driver pair is registered as a subdevice and serves as a KS(Kernel Streaming) filter(wave filter, topology filter, midi filter). All port/miniport driver pairs share a device object associated with an adapter driver.
I want to implement a wdm filter driver that supports audio EQ function. Should I place the wdm filter driver above the port class driver or above the adapter driver? Is the wdm filter driver inserted between the port class driver and the adapter driver? Additionally, I haven’t found any sample about wdm filter driver for audio device in DDK or internet. Did anyone implement wdm filter driver for audio device? May I use Kernel Streaming things (KS filter, KS node, KS pin) in wdm filter driver ?
Thanks in advance!
Yuhong