[wdmaudiodev] Vista 32 bit RTM and USB 2.0 isoch input

  • From: Stephan Kappertz <stephan@xxxxxxxxxx>
  • To: "wdmaudiodev@xxxxxxxxxxxxx" <wdmaudiodev@xxxxxxxxxxxxx>
  • Date: Tue, 19 Dec 2006 17:58:49 +0100

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?


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