On Mon, Aug 13, 2018 at 6:57 PM, Oliver Neukum <oneukum@xxxxxxxx> wrote: > On Mo, 2018-08-13 at 18:44 +0530, Muni Sekhar wrote: >> [ Please keep me in CC as I'm not subscribed to the list] >> >> Hello All, >> >> I’ve a FTDI serial device and it is not recognized if I connect >> directly to computer. However if I connect via an external USB hub >> it’s fine and I can see the FTDI serial device. What could be the >> issue and how to resolve this? >> >> >> Also one more behaviour, when I ran “lsusb” it hangs forever and ‘ps’ >> command output shows the state as “Dl+”. Any reasons for this >> behaviour? > > Impossible to tell. Switch on dynamic debugging for usbcore and your > hcd's driver and post dmesg. > Sysrq-T during the hang would also help. After enabling the dynamic debugging, I'm getting the below mentioned log: [14045.942047] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14045.942156] usb usb2-port2: status 0100, change 0001, 12 Mb/s [14046.102357] usb usb2-port2: debounce total 125ms stable 100ms status 0x101 [14046.158579] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14046.158692] usb usb2-port2: status 0100, change 0001, 12 Mb/s [14046.318662] usb usb2-port2: debounce total 125ms stable 100ms status 0x101 [14046.374689] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14046.374798] usb usb2-port2: status 0100, change 0001, 12 Mb/s [14046.535001] usb usb2-port2: debounce total 125ms stable 100ms status 0x101 [14046.591050] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14046.591161] usb usb2-port2: status 0100, change 0001, 12 Mb/s [14046.751382] usb usb2-port2: debounce total 125ms stable 100ms status 0x101 [14046.807415] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14046.807527] usb usb2-port2: status 0100, change 0001, 12 Mb/s [14046.967725] usb usb2-port2: debounce total 125ms stable 100ms status 0x101 [14047.023761] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14047.023872] usb usb2-port2: status 0100, change 0001, 12 Mb/s [14047.184025] usb usb2-port2: debounce total 125ms stable 100ms status 0x101 [14047.240078] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14047.240189] usb usb2-port2: status 0100, change 0001, 12 Mb/s [14047.400373] usb usb2-port2: debounce total 125ms stable 100ms status 0x101 [14047.456425] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14047.456537] usb usb2-port2: status 0100, change 0001, 12 Mb/s [14047.616685] usb usb2-port2: debounce total 125ms stable 100ms status 0x101 [14047.672654] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14047.672749] usb usb2-port2: status 0100, change 0001, 12 Mb/s [14047.833074] usb usb2-port2: debounce total 125ms stable 100ms status 0x101 [14047.888951] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14047.889006] usb usb2-port2: status 0100, change 0001, 12 Mb/s [14048.049388] usb usb2-port2: debounce total 125ms stable 100ms status 0x101 [14048.105450] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14048.105560] usb usb2-port2: status 0100, change 0001, 12 Mb/s [14048.265730] usb usb2-port2: debounce total 125ms stable 100ms status 0x101 [14048.321776] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14048.321892] usb usb2-port2: status 0100, change 0001, 12 Mb/s [14048.482047] usb usb2-port2: debounce total 125ms stable 100ms status 0x101 [14048.538083] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14048.538193] usb usb2-port2: status 0100, change 0001, 12 Mb/s [14048.698410] usb usb2-port2: debounce total 125ms stable 100ms status 0x101 [14048.754471] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14048.754581] usb usb2-port2: status 0100, change 0001, 12 Mb/s [14048.914753] usb usb2-port2: debounce total 125ms stable 100ms status 0x101 [14048.970807] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14048.970916] usb usb2-port2: status 0100, change 0001, 12 Mb/s [14049.131055] usb usb2-port2: debounce total 125ms stable 100ms status 0x101 [14049.187091] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14049.187200] usb usb2-port2: status 0100, change 0001, 12 Mb/s [14049.347454] usb usb2-port2: debounce total 125ms stable 100ms status 0x101 [14049.403500] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14049.403610] usb usb2-port2: status 0100, change 0001, 12 Mb/s [14049.563813] usb usb2-port2: debounce total 125ms stable 100ms status 0x101 [14049.619721] hub 2-0:1.0: state 7 ports 6 chg 0000 evt 0004 [14049.619778] usb usb2-port2: status 0100, change 0001, 12 Mb/s > > Regards > Oliver > -- Thanks, Sekhar
