3 Replies Latest reply on Aug 13, 2019 2:38 PM by MiCh_3303231

    CY7C65632 USB-Hub Issues in Linux



      I'm having a very strange problem with my USB hub in Linux (Debian 9, Kernel 4.14). I started with the CY7C65631 chip, then changed to the CY7C65632 hoping the problem would go away since this seems to be the 'preferred' chip. Initially, the problem was solved, but now it's back as we're trying to go into production, naturally. The problem occurs with one peripheral in particular - the Omron Microscan MV-30. It's a USB 2.0 device that mounts as a network interface. There are also 2 FTDI chips permanently connected on the PCB that always work fine. The camera also works fine under Windows, but the device fails to enumerate when using the CY7C65632 hub in Linux. The strangest part is that I can add any other non-powered USB hub after the CY7C65632 hub, and everything works fine... I don't really know where to start with debugging that issue, so hoping someone can point me in the right direction. dmesg capture below from failure and success. There seem to be errors in both cases, but one manages to actually work.






        • 1. Re: CY7C65632 USB-Hub Issues in Linux



          -Please send us the USB traces between the hub and PC for us to check the descriptor errors.

          -Could you try connecting any other USB device such as another FTDI chip on the same port instead of the camera?

          -Does the same configuration without the second hub work under Windows?


          Best Regards,


          • 2. Re: CY7C65632 USB-Hub Issues in Linux

            Thanks for your reply. Sorry, I should've mentioned that I can connect any other device I can think of - such as USB Drive, and it works. The camera also works fine with the hub under Windows. Also worth noting is that the Debian 9 Linux system is a Beaglebone Black SBC.


            I have captures from linux usbmon. Let me know if you need some other kind of capture.


            Failure Trace

            Working Trace




            • 3. Re: CY7C65632 USB-Hub Issues in Linux

              Not sure if this clears anything up, but it appears that Linux always manages to mount the camera if I reconnect the upstream connector after the camera is powered on (possible since the hub is self-powered). It almost always fails if I reconnect the downstream port to the camera and allow the camera to go through its normal boot process. Unfortunately, I can't just connect in that order since this goes in a piece of equipment.


              As before, any combination of reconnecting works in Windows, and adding any cheap junk hub in between my hub and the camera makes it work fine regardless of the connection order.