USB驱动问题：插入USB设备后发送事件的次数

android设备在机身旁边的usb插入时会发送多次CONFIGED通知，还有多次CONNECTED通知
  651.111175] PC detected
[  651.345611] android_work: sent uevent USB_STATE=CONNECTED
[  651.352996] android_work: sent uevent USB_STATE=DISCONNECTED
[  651.429107] android_work: sent uevent USB_STATE=CONNECTED
[  651.455627] android_usb gadget: high speed config #1: android
[  651.464385] android_work: sent uevent USB_STATE=CONFIGURED
[  655.198364] omap_hdq omap_hdq.0: TX wait elapsed
[  655.331176] omap_hdq omap_hdq.0: TX wait elapsed
[  655.463165] omap_hdq omap_hdq.0: TX wait elapsed
[  655.596038] omap_hdq omap_hdq.0: TX wait elapsed
[  655.729553] omap_hdq omap_hdq.0: TX wait elapsed
[  655.862335] omap_hdq omap_hdq.0: TX wait elapsed
[  655.995208] omap_hdq omap_hdq.0: TX wait elapsed
[  656.128143] omap_hdq omap_hdq.0: TX wait elapsed
[  656.215637] android_work: sent uevent USB_STATE=DISCONNECTED
[  656.275207] android_work: sent uevent USB_STATE=CONNECTED
[  656.283355] android_work: sent uevent USB_STATE=DISCONNECTED
[  656.356811] android_work: sent uevent USB_STATE=CONNECTED
[  656.825592] android_usb gadget: high speed config #1: android
[  656.832855] android_work: sent uevent USB_STATE=CONFIGURED

即使把ADB关掉，也还是有两次的CONNECTED和CONFIGURED事件。请问这要怎么理解？ --------------------编程问答--------------------

补充：移动开发 ,  Android