Hi All, I'm having trouble with USB 2.0 isoch input streams under Vista 32 bit RTM:I'm submitting four URBs at streaming startup. Each URB represents 32*8 isoch packets. All URBs have the USBD_START_ISO_TRANSFER_ASAP flag set. Every time an URB is finished, a new one gets submitted with the USBD_START_ISO_TRANSFER_ASAP flag. This code worked fine under Win XP. The time from submitting the USB to stream startup as monitored with an USB analyzer was always less then 100 ms. I didn't see any hardware problems like USBD_STATUS_ISO_NOT_ACCESSED_BY_HW or URBs marked with USBD_STATUS_ISOCH_REQUEST_FAILED.
Now under Vista, at streaming startup I'm _always_ getting back bad packets with USBD_STATUS_ISOCH_REQUEST_FAILED and/or almost all IsoPackets marked with USBD_STATUS_ISO_NOT_ACCESSED_BY_HW. Even worse, I'm getting back the bad packets after up to 2 seconds, causing a large delay in my streaming startup routine. After submitting new URBs from the callback for a few times I'm finally getting stable streaming.
This problem doesn't seem to be hardware related. I tried several USB controllers with the same result. However, if isoch streams were running before, restarting them usually causes a much smaller delay from stream startup to stable streaming.
Any idea how to fix this issue? Thanks, Stephan ****************** 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/