I'm making a burn-in test (see serialtest.py http://pastebin.com/pz47gaar) for our devices, that have built-in FTDI chips. If FT2232C is attached directly to the USB host controller port, the tests run properly. If I connect the chip to a USB-hub some of the tests show timeout errors (read() routine). On the newer host with USB3.0 this issue occurs on all USB ports where I attach FT2232C. I tried kernels 3.2, 3.5 and 3.8. The test procedure opens two ports, exchanges data and closes ports. If I don't open/close ports I don't encounter this issue. The FT4232H has no problems whether I attach it to USB HC or via HUB. Any idea how to workaround the problem? To reproduce the issue install python-serial package and execute the test as super user: serialtest.py -n 100 /dev/ttyUSB0 /dev/ttyUSB1 at the end of 100 cycles you'll be notified, if errors occurred. Best regards, Yegor -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
