我的Ubuntu 12.04系统上一直都不能正常连接我的Galaxy Nexus 3手机，今天下定决心要解决这个问题。Google了一下，找到了解决的办法。
首先要更新MTP的库，据说Ubuntu 13.10的MTP库已经很好用了，网上有可以直接提供好的源可以直接下载。
sudo add-apt-repository ppa:langdalepl/gvfs-mtp
Enter your user password and than you’ll be shown following text:
You are about to add the following PPA to your system:
These builds of gvfs have my native mtp backend backported from gvfs master. Use this to easily access MTP based devices with Nautilus.
More info: https://launchpad.net/~langdalepl/+archive/gvfs-mtp
Press [ENTER] to continue or ctrl-c to cancel adding it
Hit the Enter Key. After this is done you need to type following command, which updates the package list:
sudo apt-get update
After this was successful you need to upgrade the installed packages with:
sudo apt-get upgrade
然后就是发现这样还是不行，会弹出USB错误的提示，有人提示说要加Android在ubuntu中的连接规则。
3. Configure 51-android.rules:
sudo gedit /etc/udev/rules.d/51-android.rules
paste the following at the end of the file (if the file does not exist then just paste):
#LG - Nexus 4
SUBSYSTEM=="usb", ATTR{idVendor}=="1004", MODE="0666"
#Samsung - Nexus 7 & 10
SUBSYSTEM=="usb", SYSFS{idVendor}=="18d1", MODE="0666"
Save and exit.
4. Make the file executable:
sudo chmod +x /etc/udev/rules.d/51-android.rules
5. Restart udev
sudo service udev restart