LInux Power Management 办法总结

因为Gnome3中没有S3/S4选项，RHEL7做S3 一定要用： systemctl suspend

不用echo 命令，因为系统调用不同：

Technical details

XFCE(GUI), or systemctl suspend -> systemd-logind -> systemd -> systemd-sleep -> linux kernel.

It's possible to hook into this in different ways, in each of the three different links that start systemd :). Your script in /etc is run by something installed in one of the latter two. See man systemd-sleep, and man systemd.special. Unfortunately the exact ways you use these hooks are not documented very well right now. (The systemd level in particular is in need of a bit of love).

As for the first possible hook: the logind "inhibitor" system is intended for use by GUI apps. It involves receiving DBus signals.