inxi short-form reports my system as:
CPU[-Dual core Intel Core2 Duo T6400 (-MCP-) clocked at 1200.000 Mhz-] Kernel[-3.0.0-1-amd64 x86_64-] Up[-20 min-] Mem[-288.6/3018.4MB-] HDD[-250.1GB(38.1% used)-] Procs[-126-] Client[-Shell-] inxi[-1.4.23-]
Graphics are nVidia G93. Ethernet is Realtek, wireless is Intel. Swap-file is 2X installed RAM. I do not have consistent results with suspend/hibernate on any Linux distro unless my swap file is this large. Check yours and be certain it is sufficient in size.
Initially neither suspend nor hibernate would work. Both would shutdown X, disconnect the keyboard and leave a blinking horizontal cursor in the upper left corner and go no further. There turned out to be two parts to this problem, both of which must be solved for suspend/hibernate to work.
1. /etc/initramfstools/conf.d/resume must contain the proper UUID for your swap-file. You can determine this by opening a terminal and doing:
You should see a list of UUID numbers for each of your partitions, one of which will be your swap file. Note that these are in the form UUID="123ab456 ..." Those quote marks are going to disappear as you work through this, so ignore those and just check that the number given by blkid matches the number in your resume file.
My resume file initially contained the UUID number for my Home partition, why I do not know. If yours is incorrect as mine was, open a terminal and do:
sudo update-initramfs -u
Now check the resume file again using Nautilus. You should see a string in this form, UUID=1234abc5678... There will be no quote marks. If the number now matches the number given for your swap file by blkid you are good. Close up and we'll go to step two.
2. Every other time that I have solved this problem, pointing to the correct swap-file has done the trick. Not so with LMDE oddly enough. It seems that we must both configure and use your wireless capability. (I tested this to be certain. Merely configuring your wireless will not be enough.)
So if you have not done it use "edit connections" and fully configure your wireless capability. Then check the box that makes it available to "any user" so that it will start by default. This is important. Now when you start LMDE your wireless will be active even if you usually connect using Ethernet. Together with the UUID fix, if you needed it, this should allow both hibernate and suspend work for you though I cannot explain why it does.
3. Now let's test one more time. We will do suspend first. You should get a full suspend using either the power-off menu or by closing your laptop lid. If closing your lid does not work, then check your Power Management Preferences to make sure you have it selected. It then should work. To resume just raise the lid. You should hear your HDD spin up at which point just tap your space-bar. You will be asked for your password to unlock your desktop and back in you will go.
Hibernate is slower but it should work. First make certain you open at least one application on your desktop. (I opened both Abiword and Gnumeric, which I use.) Select Hibernate from your Quit menu. X will turn off immediately (the dreaded horizontal cursor returns!), then the HDD will spin up as it writes your RAM contents to the HDD and then your machine will power-down. To resume press your power key once. Your machine will come up and boot GRUB. Select LMDE and log in as you normally do. This is going to look like a normal cold start but the difference here is that your desktop will show your open applications just as you left them. In other words Hibernate has done a resume just as it should.
Note that I do not know if this fix will survive a future kernel upgrade. If it does not the culprit probably will be the resume file pointing to the wrong partition once again. So we may have to fix that when we do a kernel upgrade. Time will tell.
One last point: If you do an update/upgrade and you have both Ethernet and Wireless active, turn off the wireless. In my earlier experience with sidux timing differences between the two corrupted compressed downloads. Then if you anticipate using either suspend or hibernate just make certain that Wireless is active.