我安装了 Ubuntu 14.04 LTS，但它无法识别笔记本电脑的触摸板。这是什么原因造成的？
这里有一些输出：
xinput list
输出：
⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ 2.4G RX id=11 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
↳ Power Button id=6 [slave keyboard (3)]
↳ Video Bus id=7 [slave keyboard (3)]
↳ Video Bus id=8 [slave keyboard (3)]
↳ Sleep Button id=9 [slave keyboard (3)]
↳ USB Camera id=10 [slave keyboard (3)]
↳ AT Translated Set 2 keyboard id=12 [slave keyboard (3)]
synclient touchpadoff=0
输出：
Couldn't find synaptics properties. No synaptics driver loaded?