我在使用一块imx6 sabre-sd开发板，它有一个USB HUB芯片（USB2514B）。
大多数时候工作正常，但有时一段时间之后，USB口没有电源输出。
通过dmesg，可以看到如下信息。我如何能知道故障何时发生？
故障发生时，我如何通过软件复位USB HUB？
I am using a imx6 sabre-sd board , it has a USB HUB chip (USB2514B). Most of the time working well,
but sometimes after a period of time , USB port no power output.
use dmesg command, I can see the following messages.
How do I know when a fault occurs ?
When a fault occurs , how do I reset the USB HUB?
：
<6>android_work: sent uevent USB_STATE=DISCONNECTED
<7>fsl_gadget_disconnect_event: udc enter low power mode
<3>option: option_instat_callback: error -2
<3>option: option_instat_callback: error -2
<3>hub 2-1:1.0: hub_port_status failed (err = -110)
<3>hub 2-1:1.0: hub_port_status failed (err = -110)
<3>hub 2-1:1.0: cannot disable port 2 (err = -110)
<4>------------[ cut here ]------------
<4>WARNING: at /media/myandroid/work/20140609/kernel_imx/net/sched/sch_generic.c
:255 dev_watchdog+0x284/0x2a8()
<6>NETDEV WATCHDOG: eth1 (cdc_ether): transmit queue 0 timed out
<4>Modules linked in: cfg80211
<4>[<c004cfc4>] (unwind_backtrace+0x0/0x138) from [<c0081eec>] (warn_slowpath_co
mmon+0x4c/0x64)
<4>[<c0081eec>] (warn_slowpath_common+0x4c/0x64) from [<c0081f98>] (warn_slowpat
h_fmt+0x30/0x40)
<4>[<c0081f98>] (warn_slowpath_fmt+0x30/0x40) from [<c04aa038>] (dev_watchdog+0x
284/0x2a8)
<4>[<c04aa038>] (dev_watchdog+0x284/0x2a8) from [<c008d950>] (run_timer_softirq+
0xf8/0x248)
<4>[<c008d950>] (run_timer_softirq+0xf8/0x248) from [<c00879b8>] (__do_softirq+0
xac/0x140)
<4>[<c00879b8>] (__do_softirq+0xac/0x140) from [<c0087ef4>] (irq_exit+0x94/0x9c)
<4>[<c0087ef4>] (irq_exit+0x94/0x9c) from [<c00461b4>] (handle_IRQ+0x50/0xac)
<4>[<c00461b4>] (handle_IRQ+0x50/0xac) from [<c004534c>] (__irq_svc+0x4c/0xe8)
<4>[<c004534c>] (__irq_svc+0x4c/0xe8) from [<c0046468>] (default_idle+0x24/0x28)
<4>[<c0046468>] (default_idle+0x24/0x28) from [<c0046778>] (cpu_idle+0xc8/0x108)
<4>[<c0046778>] (cpu_idle+0xc8/0x108) from [<c00088bc>] (start_kernel+0x29c/0x2e
c)
<4>[<c00088bc>] (start_kernel+0x29c/0x2ec) from [<10008040>] (0x10008040)
<4>---[ end trace 1857336724a8d525 ]---
<3>hub 2-1:1.0: hub_port_status failed (err = -110)
<6>otg udc vbus rising wakeup
<7>try_wake_up_udc: udc out low power mode
<6>android_work: did not send uevent (0 0 (null))
<6>android_work: sent uevent USB_STATE=CONNECTED
<6>android_work: sent uevent USB_STATE=DISCONNECTED
<6>android_work: sent uevent USB_STATE=CONNECTED
<6>android_usb gadget: high speed config #1: android
<6>android_work: sent uevent USB_STATE=CONFIGURED
: Design files, including hardware schematics