ar drone USB 需要拔掉重插才能被识别

silentstorm321f

按照MAPGPS 和 老外的帖子，
给ardrone添加了USB的驱动，dwc_otg.ko

然而飞机上电以后，加载完dwc_otg.ko
USB设备并不能第一时间被识别
需要重新拔插一下USB接口，
飞机才能识别到ttyUSB0的USB设备
开机后，不能直接识别，且dmesg如下：

[ 35.755192] hub 1-0:1.0: unable to enumerate USB device on port 1
[ 35.804582] hub 1-0:1.0: state 7 ports 1 chg 0000 evt 0002
[ 35.804677] hub 1-0:1.0: port 1, status 0503, change 0001, 480 Mb/s
[ 35.981561] hub 1-0:1.0: debounce: port 1: total 100ms stable 100ms status 0x503
[ 36.042486] hub 1-0:1.0: port 1 not reset yet, waiting 50ms
[ 36.161591] usb 1-1: new high speed USB device using dwc_otg and address 3
[ 36.221609] hub 1-0:1.0: port 1 not reset yet, waiting 50ms
.. same for addresses 4 to 5 ..
[ 36.341940] usb 1-1: device descriptor read/64, error -71
[ 38.182773] hub 1-0:1.0: port 1 not reset yet, waiting 50ms
[ 38.307717] usb 1-1: new high speed USB device using dwc_otg and address 6
[ 38.723069] usb 1-1: device not accepting address 6, error -71
[ 38.723181] hub 1-0:1.0: unable to enumerate USB device on port 1
[ 38.723233] hub 1-0:1.0: state 7 ports 1 chg 0000 evt 0002
[ 38.723279] hub 1-0:1.0: port 1 enable change, status 00000501

希望了解的朋友能给予帮助，最好能给我简单分析一下原理，我挺想自己搞dwc_otg的驱动的，但是不知道从哪里入手，大家给点建议吧。