Do you want to Suspend to RAM or Disk? (suspend to RAM is faster and requires power ONLY to ram)?
More details:
pm-suspend
During suspend most devices are shutdown, and system state is saved
in RAM. The system still requires power in this state. Most modern
systems require 3 to 5 seconds to enter and leave suspend, and most
laptops can stay in suspend mode for 1 to 3 days before exhausting
their battery.
pm-hibernate
During hibernate the system is fully powered off, and system state
is saved to disk. The system does not require power, and can stay
in hibernate mode indefinitely. Most modern systems require 15 to
45 seconds to enter and leave hibernate, and entering and leaving
hibernate takes longer when you have more memory.
NOTE: there is also a hybrid mode which is in between suspend to RAM and Disk.
Find what states are supported by your laptop, for example (supports both to ram and disk):
cat /sys/power/state
mem disk
You can do it from command line anyway:
Option 1: use pm-utils
(need to install the package and user needs to have privilege to do suspend)
Suspend to RAM: sudo pm-suspend
Hibernate (to Disk): sudo pm-hibernate
Option 2: directly change sysfs
(requires root privilege)
Suspend to RAM: echo "mem" > /sys/power/state
Hibernate (to Disk): echo "disk" > /sys/power/state
Refere to System Power Management State
upower -d | grep can-hibernate
andfree -m
in your question?can-hibernate: no
-----------------------------------------------------------------total used free shared buffers cached Mem: 7687 6246 1440 0 145 2904 -/+ buffers/cache: 3196 4491 Swap: 7887 1183 6704
free -m
andcan-hiberate
sudo pm-hibernate
really should work without these steps. This is also outlined in the accepted answer there.