苏河滔 wrote: > Dear all: > > such as: > 1)implement some special sound effects, > 2)communicate with a custom application for custom IOCTL This is not a wise plan. Consumers today expect to be able to plug in an audio device and have it work immediately, without worrying about installing a driver. Custom sound effects are the responsibility of an application, not a driver. In Vista and beyond, you can use a "sysfx APO" (system effects audio processing object) to do sound effects. Those are DLLs that reside in user mode, where they do not impact system stability. There are white papers on MSDN and sample APOs in the WDK. It is possible to write an upper filter driver to usbaudio.sys to implement a custom IOCTL, but what would your custom IOCTL do? Your device is only supposed to respond to requests that are part of the USB Audio Class specification. Thus, you shouldn't need to do any special processing. -- Tim Roberts, timr@xxxxxxxxx Providenza & Boekelheide, Inc. ****************** WDMAUDIODEV addresses: Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx Subscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe Unsubscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx URL to WDMAUDIODEV page: http://www.wdmaudiodev.com/