Tdtsai wrote: > > Hi > I writted a driver for an USB Audio Device base on PortCls. I tested it by > HCT 11.2 in Windows XP SP1. I pass most test item. But in test item KS Audio > Position Accuracy. It say my device is an USB Device and can't test item KS > Audio Position Accuracy. Do this my driver's mistake? > According to Microsoft you are not supposed to use the PortCls for USB devices. The DDK says you should comply with the USB sound spec. so Windows will use its internal drivers. The fact that this results in a high latency (Kmixer) which makes the device unusable is not an issue for MS. The only 'proper' way would be to write you're own KS driver, which is a lot of work. Regards, Bart ****************** 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/