On Wed, Apr 3, 2013 at 9:12 AM, Yegor Yefremov <yegorslists@xxxxxxxxxxxxxx> wrote: > On Tue, Apr 2, 2013 at 4:36 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: >> On Tue, 2 Apr 2013, Yegor Yefremov wrote: >> >>> On Tue, Apr 2, 2013 at 4:14 PM, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: >>> > On Tue, 2 Apr 2013, Yegor Yefremov wrote: >>> > >>> >> 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? >>> > >>> > If you use a different type of hub, does the test work? >>> >>> So far I tested with 3 different hub chips SMSC, GL (USB2.0) and one >>> USB3.0 hub - no difference. >> >> In that case, try collecting two usbmon traces showing what happens >> during the test. In one trace, connect the FT2232C directly to the >> computer port; in the other, go through the GL hub. See >> Documentation/usb/usbmon.txt for instructions. > > Will do. The proper script with cycles support '-n' http://dl.dropbox.com/u/6486923/serialtest.py raw text HCD: http://dl.dropbox.com/u/6486923/ftdi_sniff_hcd.out tcpdump HCD: http://dl.dropbox.com/u/6486923/ftdi_sniff_hcd.pcap HCD sniffs show 2 cycles raw text HUB: http://dl.dropbox.com/u/6486923/ftdi_sniff_hub.out tcpdump HUB: http://dl.dropbox.com/u/6486923/ftdi_sniff_hub.pcap HUB sniffs have different number of cycles regarding when the test failed. Let me know if you need more info or sniffs. 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
