ubuntu usb

刚安装好的VirtualBox里的客户机无法使用主机里的USB设备，设置时 提示有权限问题。

针对此问题，可如下解决。

* 增加用户组usbfs

sudo groupadd usbfs

* 查看usbfs的gid

cat /etc/group | grep usbfs

在我的系统上输出

usbfs:x:1002:

* 把自己所用的用户增加到usbfs组

usbfs:x:1002:yang

* 编辑/etc/fstab文件，添加下面两行，注意你的gid可能不是1002

# 1002 is USB group ID
none /proc/bus/usb usbfs devgid=1002,devmode=664 0 0

* 重新起动后，应该就可以在客户机中使用USB设备了。在客户机里使用USB设备前要先在主机里卸载。

* 补充

9.4.6. USB not working

If USB is not working on your Linux host, make sure that the current user has permission to access the USB filesystem (usbfs), which VirtualBox relies on to retrieve valid information about your host's USB devices.

The permissions for usbfs can be changed by editing the /etc/fstab file.

For example, most Linux distributions have a user group called usb or similar, of which the current user must be a member. To give all users of that group access to usbfs, make sure the following line is present:

# 85 is the USB group
none /proc/bus/usb usbfs devgid=85,devmode=664 0 0

Replace 85 with the group ID that matches your system (search /etc/group for "usb" or similar).

Alternatively, if you don't mind the security hole, give all users access to USB by changing "664" to "666".

没想到，进入xp后还是不能识别usb设备（无论我插上usbkey后再启动xp还是启动xp后再插上usbkey），我找了很久，才在wiki里 面的另一篇文章提到的方法解决了我的难题。http://wiki.ubuntu.org.cn/index.php?title=UbuntuHelp:VirtualBox&variant=zh-tw#USB

代码为：

代码:
derek@ubuntu:~$ ls -l /proc/bus/
总用量 0
dr-xr-xr-x 2 0 2007-09-06 21:25 input
dr-xr-xr-x 2 root root 0 2007-09-06 21:25 pccard
dr-xr-xr-x 4 root root 0 2007-09-06 21:25 pci
drwxr-xr-x 6 root root 0 2007-09-07 02:54 usb
derek@ubuntu:~$ sudo chown -R root:vboxusers /proc/bus/usb
Password:
derek@ubuntu:~$ ls -l /proc/bus/
总用量 0
dr-xr-xr-x 2 root root      0 2007-09-06 21:28 input
dr-xr-xr-x 2 root root      0 2007-09-06 21:28 pccard
dr-xr-xr-x 4 root root      0 2007-09-06 21:28 pci
drwxr-xr-x 6 root vboxusers 0 2007-09-07 02:54 usb

完成上述命令之后启动xp，马上usbkey就被识别了。