ubuntu 14.04 LTS 輸入密碼界面卡死，（升級過的K29)。無法調出tty1,
重啓選擇Ubuntu高級選項，進入安全模式，選擇network Enablenetwork
然後屏幕下方出現tty1
sudo 登陸之後執行如下：
Method #3 How to Fix Ubuntu login screen loop
If even both did not work for you, try the last one! Please make sure you are connected to active internet. Check this out!Step 1- Uninstall and reinstall Ubuntu lightdm. Run the following :
dian@foss:~$ sudo apt-get purge lightdm
dian@foss:~$ sudo apt-get install lightdm
dian@foss:~$ dpkg-reconfigure lightdmStep 2 - Once reconfigured, now reboot.
【http://www.linuxslaves.com/2016/05/3-ways-fix-ubuntu-gets-stuck-login-loop.html】
ok了。