Hi all I have some problem with IRP_MN_QUERY_INTERFACE request . I have implemented our driver as an bus driver with two audio child devices . In windows 2K , I never received any IRP_MN_QUERY_INTERFACE request , but for windows XP , I receive this request . Can anybody let me know what is the difference in the implementation of ks.sys ? Or what I need to do in the child device when I get this request ? Thanks in advance srinivasa __________________________________________________ Do you Yahoo!? HotJobs - Search new jobs daily now http://hotjobs.yahoo.com/ ****************** 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.de/