We have an issue with a larger (4096 byte) transfer to EP0.  On Windows 8 with SuperSpeed, this transfer is stalling the control transfer.  Smaller (64 byte) transfers work.  And the 4096-byte transfer seems to be working in High Speed mode on USB 2.0 ports.

What is the proper way to capture a transfer of this size within the vendor request processing?

Will the following work?

CyU3PUsbGetEP0Data(4096, count, &readCount);

Since EP0 size is set to 64 bytes, but the entire transfer is much larger, when does the USB setup event get called?  Is it likely that onyl part of the data is received by each call to GetEP0Data, thus requiring multiple calls?

A touch more information on this.

With HighSpeed ports, I can read the entire 4096 bytes.

With SuperSpeed ports, I can read 512 bytes.  Not 1024.  The call to CyU3PUsbGetEP0Data returns Cy_U3P_ERROR_TIMEOUT if the length specified is greater than 512.

We're still having this issue.  With a USB 3.0 bus analyzer, we note that IN transfers of 1024 bytes time out for some reason.

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Is anyone else using Windows 8?  Any issues with larger EP0 transfers?

Microsoft has said that a known issue existed with Windows 8 (Consumer Preview) and the ASMedia controller that has problems with control transfers > 512 bytes.  This does not appear to be an issue with the Renesas controller.  According to them, the problem has a workaround and will be issued in the next Win8 release.

 Are there any updates on this issue?

I've win 8441 and I still can't send configuratin descriptor larger then 512 bytes .

 http://social.msdn.microsoft.com/Forums/en-US/wdk/thread/74097a22-fab2-440a-8e17-65dd0c968568/

The above thread says that the workaround will be added to the next release of the Windows 8.

Have you tested with the Windows 8 Release Preview version.