8168的USB无法识别U盘

各位大神：

  你们好！！我们现在用8618在读取U盘时，会出现无法识别U盘，重启之后又可以识别到U盘，反反复复的！会是什么问题导致？

user4522451：

附上原理图：

Chris Meng：

回复 user4522451:

Huang Yun，

你是否有测量一下，当U盘插入的时候，VBUS 5V是否有跌落得很厉害？

james ZHANG3：

回复 Chris Meng:

你好 ，

     我也遇到类似的问题 ，我的机子也会随机出现无法读取到usb的请求 我是使用DM368 IPNC5.1方案 linux系统2.6.37 当出现无法加载USB 会有打印信息

[ 7.465654] iscsi: registered transport (tcp)[ 7.994887] musb-hdrc: version 6.0, host, debug=0[ 8.461077] musb-hdrc musb-hdrc: dma type: dma-cppi3[ 8.482654] musb-hdrc: ConfigData=0x06 (UTMI-8, dyn FIFOs, SoftConn)[ 8.482740] musb-hdrc: MHDRC RTL version 1.500 [ 8.482785] musb-hdrc: setup fifo_mode 2[ 8.482849] musb-hdrc: 9/9 max ep, 4032/4096 memory[ 8.483028] musb-hdrc musb-hdrc: MUSB HDRC host driver[ 8.483432] musb-hdrc musb-hdrc: new USB bus registered, assigned bus number 1[ 8.524528] hub 1-0:1.0: USB hub found[ 8.524735] hub 1-0:1.0: 1 port detected[ 8.534293] musb-hdrc musb-hdrc: USB Host mode controller at fec64000 using DMA, IRQ 12[ 8.972020] usb 1-1: new full speed USB device using musb-hdrc and address 2[ 9.090678] usb 1-1: device descriptor read/64, error -71[ 9.099397] loop: module loaded[ 9.331564] tun: Universal TUN/TAP device driver, 1.6[ 9.331648] tun: (C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>[ 9.352598] usb 1-1: device descriptor read/64, error -71[ 9.503308] console [netcon0] enabled[ 9.503376] netconsole: network logging started[ 9.583310] usb 1-1: new full speed USB device using musb-hdrc and address 3[ 9.701097] usb 1-1: device descriptor read/64, error -71[ 9.789565] PPP generic driver version 2.4.2[ 9.888197] PPP Deflate Compression module registered[ 9.952076] usb 1-1: device descriptor read/64, error -71[ 10.182016] usb 1-1: new full speed USB device using musb-hdrc and address 4[ 10.600899] usb 1-1: device not accepting address 4, error -71[ 10.750564] usb 1-1: new full speed USB device using musb-hdrc and address 5[ 11.172383] usb 1-1: device not accepting address 5, error -71[ 11.195632] hub 1-0:1.0: unable to enumerate USB device on port 1[

出现此问题 无论怎么软件重启都没用 一直还是一样的问题 但是 如果重新断电重启 则又能正常检测到 请问这是为什么？