Hello. I have a SCL3711 USB NFC adapter alongside a Broadcom Bluetooth USB dongle. When I don't have the Bluetooth adapter connected everything works fine while reading and writing to the SCL3711 USB device. As soon as I connect the Bluetooth dongle and the HCI device is brought up (by bluetoothd) I get strange results accessing the other USB device (the SCL3711). Namely, commands only succeed half the time. This is the usb trace after I connect the Bluetooth dongle: d4ee76c0 2655843959 S Bo:2:003:4 -115 6 = 0000ff00 ff00 d4ee76c0 2655856308 C Bo:2:003:4 0 6 > d4ee76c0 2655858073 S Bo:2:003:4 -115 6 = 0000ff00 ff00 d4ee76c0 2655989500 C Bo:2:003:4 -2 0 d4ee76c0 2655995705 S Bo:2:003:4 -115 6 = 0000ff00 ff00 d4ee76c0 2656011106 C Bo:2:003:4 0 6 > d4ee76c0 2656014393 S Bo:2:003:4 -115 6 = 0000ff00 ff00 d4ee76c0 2656145295 C Bo:2:003:4 -2 0 d4ee76c0 2656148657 S Bo:2:003:4 -115 9 = 0000ff02 fed4022a 00 d4ee76c0 2656164635 C Bo:2:003:4 0 9 > d4ee76c0 2656166040 S Bi:2:003:4 -115 256 < d4ee76c0 2656167787 C Bi:2:003:4 -121 13 = 0000ff06 fad50333 020707e5 00 d4ee76c0 2656169026 S Bi:2:003:4 -115 256 < d4ee76c0 2656303719 C Bi:2:003:4 -2 0 We can see that half of the commands fail with a timeout. Now I run "hciconfig hci0 down" to disable my USB bluetooth dongle: d4ee7240 2675733982 S Co:2:004:0 s 20 00 0000 0000 0003 3 = 030c00 d4ee7440 2676001605 C Ii:2:004:1 -2:1 0 d4ee7bc0 2676024582 C Bi:2:004:2 -2 0 d4ee7b40 2676028239 C Bi:2:004:2 -2 0 And I run my test program again: d4ee71c0 2686007833 S Bo:2:003:4 -115 6 = 0000ff00 ff00 d4ee71c0 2686013219 C Bo:2:003:4 0 6 > d4ee71c0 2686013571 S Bo:2:003:4 -115 6 = 0000ff00 ff00 d4ee71c0 2686016715 C Bo:2:003:4 0 6 > d4ee71c0 2686017760 S Bo:2:003:4 -115 6 = 0000ff00 ff00 d4ee71c0 2686021020 C Bo:2:003:4 0 6 > d4ee71c0 2686022987 S Bo:2:003:4 -115 6 = 0000ff00 ff00 d4ee71c0 2686024911 C Bo:2:003:4 0 6 > d4ee71c0 2686025995 S Bo:2:003:4 -115 9 = 0000ff02 fed4022a 00 d4ee71c0 2686027903 C Bo:2:003:4 0 9 > d4ee71c0 2686029519 S Bi:2:003:4 -115 256 < d4ee7240 2686030809 C Co:2:004:0 0 3 > d4ee71c0 2686032590 C Bi:2:003:4 -121 13 = 0000ff06 fad50333 020707e5 00 d4ee71c0 2686034022 S Bi:2:003:4 -115 256 < d4ee71c0 2686169152 C Bi:2:003:4 -2 0 d4ee7bc0 2693792018 S Bo:2:003:4 -115 6 = 0000ff00 ff00 d4ee7bc0 2693802963 C Bo:2:003:4 0 6 > d4ee7bc0 2693805235 S Bo:2:003:4 -115 6 = 0000ff00 ff00 d4ee7bc0 2693808314 C Bo:2:003:4 0 6 > d4ee7bc0 2693810052 S Bo:2:003:4 -115 6 = 0000ff00 ff00 d4ee7bc0 2693813240 C Bo:2:003:4 0 6 > d4ee7bc0 2693813771 S Bo:2:003:4 -115 6 = 0000ff00 ff00 d4ee7bc0 2693816152 C Bo:2:003:4 0 6 > d4ee7bc0 2693817197 S Bo:2:003:4 -115 9 = 0000ff02 fed4022a 00 d4ee7bc0 2693819635 C Bo:2:003:4 0 9 > d4ee7bc0 2693820851 S Bi:2:003:4 -115 256 < d4ee7bc0 2693823948 C Bi:2:003:4 -121 6 = 0000ff00 ff00 d4ee7bc0 2693824794 S Bi:2:003:4 -115 256 < d4ee7bc0 2693832870 C Bi:2:003:4 -121 13 = 0000ff06 fad50333 020707e5 00 The device is working correctly again... Can this be a kernel USB bug or a bug on one of the devices? Is there any further info I can add to help diagnose the problem? I've tried Debian stable and unstable and this problem happens on both. This seems related to http://libusb.6.n5.nabble.com/Why-does-Linux-forget-the-USB-toggle-bit-of-my-device-td6829.html but I'm using a more recent kernel version which should have prevented this. Thanks and best regards, André -- 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