[libusb] Issue with 'unsupported API call for 'open' (unrecognized device driver)'

[Tim Roberts]

Libusb version v1.0.20.11014 built from scratch with VS2015 running on
Windows 10 x64P. Target device is FX3 w/ custom firmware. WinUSB driver
installed using Zadig 2.3. WinUSB v6.1.7600.16385.
I am 100% certain I've missed something really obvious but all calls to
'open' end up going to the default backend handler.

The xusb log seems to show a device 04B4:0007 (interface 3) at address
2.20, and a device 04B4:00FF at address 2.20, plus a 04B4:0007 device at
address 2.19. That's fairly peculiar. Do you have multiple Cypress
devices installed? Does your device change its personality on the fly?

Does "usbview" show your descriptors properly?

Understand that you can't ship a device with Cypress' VID number. It's
perfectly fine for your testing, but you will want your own number
before you ship.

[g***@novadsp.com]

Hello Tim

Do you have multiple Cypress devices installed?
Does your device change its personality on the fly?

This is a Cypress FX3 explorer board. So one device is the FX3 controller
and the other the on-board UART/JTAG.

Ref:
http://www.cypress.com/documentation/development-kitsboards/cyusb3kit-003-ez
-usb-fx3-superspeed-explorer-kit

Does "usbview" show your descriptors properly?

Yes.

[Tim Roberts]

Post by g***@novadsp.com

Do you have multiple Cypress devices installed?
Does your device change its personality on the fly?

This is a Cypress FX3 explorer board. So one device is the FX3 controller
and the other the on-board UART/JTAG.

That doesn't explain the results in your enumeration. The enumeration reports
04B4:0007 on device 19
04B4:0007 on device 20 interface 3 and
04B4:00FF on device 20

Does the UART/JTAG have its own USB connector, or does it actually borrow an interface from your device? Does USBView show them as two separate devices, or as two interfaces on one device?
—
Tim Roberts, ***@probo.com
Providenza & Boekelheide, Inc.