I have extracted the minimal program down to a single file necessary to demonstrate the issue I am having outside the context of the larger program. At the highest level of description the USB Host (FTDI Vinculum-II) connects to a UVC camera, properly enumerates the device interfaces, end points, etc., sets up for transfer, but in the end when it finally does a vos_dev_read() (line 511), it returns with no error, and zero bytes read.  The Host -> UVC camera ioctl r/w work fine and all values retrieved from the UVC camera (multiple cameras have been used in testing) are validated properly against the USB dumps from USB Device viewer. So, the bi-direction conversation is working great, just no video data. If I change values to invalid values or unplug the camera, I do get the expected error codes.

To be clear, this derivative program does nothing with the data read beyond it writes out to the UART terminal (9600 baud, no flow-control) the number of bytes read. Bottom line; find a fix for this program and the same will work for the real program.

I know it would be finding a Unicorn with someone who has experience with the Vinculum-II USB 2.0 chip, but I believe the issues is a USB/UVC issue and not a problem with the chip or what it is attempting to do. There is a slightly larger hive mind of UVC than the FTDI host chip. I have tried to find the magic incantation; I have tried yelling 4-letter words at the chip, and have even asked nicely, “Please” to no avail. The code was original derived from FTDI’s WebCam demo program which was very poorly written and contains a large number of un-described hardcoded numeric constants.

I have looked at every USB/UVC drivers (mostly Linux and Windows) on the entire internet. Calling all USB Host gurus for help please.

Thank you!