On Thu, Jan 07, 2016 at 09:04:59AM +0800, yankun at iscas.ac.cn wrote: > Thank you Martin.There is also a doubt: how the lightdm starts > upstart? I can not find anything useful in unit files ? It's hooked up via Xsession configuration, in /etc/X11/Xsession.d/00upstart and /etc/X11/Xsession.d/99upstart. -- Colin Watson [cjwatson at ubuntu.com]