vermaden article is flawless and works perfectly on my Dell inspiron 5593 ↓
Suspend and Resume
The biggest enemies of supend/resume mechanism are bugs in your BIOS/UEFI firmware for your hardware. Sometimes disabling Bluetooth helps – that is the option for ThinkPad T420s for example. To check which suspend modes are supported on your system check the hw.acpi.supported_sleep_state MIB from sysctl(8) subsystem.
% sysctl hw.acpi.supported_sleep_state
hw.acpi.supported_sleep_state: S3 S4 S5
To enter ACPI S3 sleep state (suspend) you can use acpiconf(8) tool or zzz(8) tool.
… or with acpiconf(8) tool.
# acpiconf -s 3
Its exactly the same as stated in the zzz(8) man page.
You can also set sysctl(8) value that everytime you close your laptop lid your system will go to sleep. To achieve that put
hw.acpi.lid_switch_state=S3 into the
/etc/sysctl.conf file. No matter if you put you hardware to sleep by command or by closing the lid your laptop will resume after opening the lid. Of course if you haven’t closed the lid after the zzz(8) command you will either have to close and open the lid or push the power button to resume. Of course you may also suspend/resume desktops or even your backup server if it has its purpose. It’s not limited to laptops only.