嵌入式linux下的USB自动挂载问题

现在在做嵌入式linux下的USB自动挂载。
在系统启动的时候，首先加载USB驱动。加载过程中出现如下错误：
usb 1-2: new full speed USB device using hisilicon-ohci and address 2
usb 1-2: device descriptor read/64, error -110
usb 1-2: device descriptor read/64, error -110
usb 1-2: new full speed USB device using hisilicon-ohci and address 3
usb 1-2: device descriptor read/64, error -110
usb 1-2: device descriptor read/64, error -110
usb 1-2: new full speed USB device using hisilicon-ohci and address 4
usb 1-2: device not accepting address 4, error -110
usb 1-2: new full speed USB device using hisilicon-ohci and address 5
usb 1-2: device not accepting address 5, error -110
这是怎么回事？
虽然出现上述错误。但是当系统起来以后在控制台下还是能发现USB设备。我现在用的是U盘
能在/dev/scsi/host0/bus0/target0/lun0/目录下发现disc和part1
然后可以手动挂载。
现在我想让U盘自动挂载。写了个脚本。在加载完驱动以后马上执行挂载U盘脚本。但是挂载的时候提示
mount: Mounting /dev/scsi/host0/bus0/target0/lun0/part1 on /mnt/usb failed: No such file or directory
下面是脚本的内容：
load_usb_drv
sleep 10
if[ -r /dev/scsi/host0/bus0/target0/lun0/part1 ]
then
    mount /dev/scsi/host0/bus0/target0/lun0/part1 /mnt/usb
fi