I struggled with a similar issue in Debian 9, installed on a Lenovo G40-30 Laptop. I went into Hibernate/Sleep
and trying to initiate again the screen didn't show up although everything seemed working.
The solution is actually quite simple. It seems Linux OSs, in particular Debian and Ubuntu need at least a 4+GB swap partition for Hibernate/Sleep to work properly. If you installed with "default" configuration it
will create a Swap the same size of your actual RAM (in practice a little less). So if you have a laptop with less or equal to 4 Gb RAM and installed "default" configuration, you are probably trying to solve this issue.
Swap allocation in Linux work in two ways:
in the form of a SWAP PARTITION in your hardrive.
in the form of a SWAP FILE.
YOU CAN CREATE THE
SWAP FILE AS FOLLOWS:
sudo swapon --show
shows if you have enabled the swap option. If not look up how to do this.
sudo fallocate -l 1G /swapfile
sets the size of the swap you add to 1Gb, change to the value you need.
sudo chmod 600 /swapfile # sets the file to be owned by root
sudo mkswap /swapfile # mkswap tool to allocate swap in the file
sudo swapon /swapfile # activate the swap
sudo nano /etc/fstab # open the file to make changes permanent
Add the line
/swapfile swap swap defaults 0 0 to the file
sudo swapon --show # show if its working
sudo free -h # show Memory and Swap
IF YOU WANT TO UNDO CHANGES JUST:
sudo swapoff -v /swapfile
remove the line from
/swapfile swap swap defaults 0 0
sudo rm /swapfile # remove the swap file
SWAP SIZES ACCORDING TO RAM:
I can indicate the following table with some recommended
SWAP sizes according to your RAM. Last 3 columns are
RAM No hibernation With Hibernation Maximum
1GB 1GB 2GB 2GB
2GB 1GB 3GB 4GB
3GB 2GB 5GB 6GB
4GB 2GB 6GB 8GB
5GB 2GB 7GB 10GB
6GB 2GB 8GB 12GB
8GB 3GB 11GB 16GB
12GB 3GB 15GB 24GB
16GB 4GB 20GB 32GB
24GB 5GB 29GB 48GB
32GB 6GB 38GB 64GB
64GB 8GB 72GB 128GB
128GB 11GB 139GB 256GB
256GB 16GB 272GB 512GB
512GB 23GB 535GB 1TB
1TB 32GB 1056GB 2TB
2TB 46GB 2094GB 4TB
4TB 64GB 4160GB 8TB
8TB 91GB 8283GB 16TB
you can find thorough information on recommended SWAP sizes according to your RAM in the following link:
How much swap should I take for 1GB to 8TB of RAM on 14.04 or higher?
Credit is due for the table I added here.