Dell XPS 13 9365 2-in-1 won't resume after suspend (Ubuntu 16.04)

I recently got a new Dell XPS 13 9365 2-in-1 laptop, I've installed Ubuntu 16.04.1 on it ( kernel 4.8.0-34-generic ) and I noticed that every time I close my laptop lid ( which sends the computer in Suspend mode ) I can not return from Suspend. If I manually go into Suspend mode ( using the GUI not by closing the lid ) I also can't return from that.

Things I've already tried:

sudo apt-get update
sudo apt-get upgrade 

which for what it's worth mentioned this before finishing (not sure if it's an issue or not)

W: Possible missing firmware /lib/firmware/i915/kbl_guc_ver9_14.bin for module i915
W: Possible missing firmware /lib/firmware/i915/bxt_guc_ver8_7.bin for module i915

Some have suggested it could be a brightness issue, which can be corrected in BIOS, but if that were the case I would assume that I would be able to ssh into my machine from another computer, and I cannot ssh into it after going into Suspend (which makes me think it's not simply a brightness issue, but is in fact stuck in Suspend mode)

I tried this script posted on Ubuntu Forums which did not work. It says it's an automated way of doing what you could do manually with Ctrl+Alt+F1 and Ctrl+Alt+F7 but those shortcut keys also do nothing for me after trying to return from Suspend (they do of course work normally, when I'm not in Suspend).

I attempted to try this fix from Ubuntu Forums which references answer #7 in this other thread. I was confused as to exactly how I should substitute the "XXXX:XX:XX.X" in the example, but seeing as how it seemed like a variation on the script I tried before (also in /etc/pm/sleep.d/) I moved on to trying the next thing

I then tried this one Blank screen after resume - Dell M5510 Ubuntu 16.04 but this also didn't solve my problem

I also installed laptop-mode-tools as someone suggested, but wasn't sure how to use this to address the issue.

I should also mention that I had a wireless card issue when I first installed Ubuntu, and that was fixed this way Wireless not working on Dell XPS 13 9365 Ubuntu 16.04 I mention this because it involved updating my kernel (which again is 4.8.0-34-generic) and in one post about Suspend issues they mentioned that it could be caused by the wireless card changing its status XPS 13 9343 Failure to resume from suspend

I hope this can be fixed, thanks in advance!

systemd-sleep

The 9365 only supports suspend to idle (also called "freeze" in linux). It will show the behavior you describe when you try to use suspend to ram, which is the default unfortunately.

This answer is similar to Nick's answer that proposes to change the linux command line using grub. In fact my proposal has exactly the same effect, but by editing another system file.

Just add the following to the file /etc/systemd/sleep.conf:

[Sleep]
SuspendState=freeze

See the systemd-sleep.conf manual for further information.

finally! a solution! @DenisPitza posted in the comments to my question a solution that worked for me! his original post is here i'm reposting his answer below for convenience:

to make permanent the solution proposed by @user8211580 you should edit your groub config file with:

sudo vi /etc/default/grub

edit the line containing

GRUB_CMDLINE_LINUX_DEFAULT

and make sure to include "mem_sleep_default=s2idle" like:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash mem_sleep_default=s2idle"

and then reload grub:

sudo update-grub

Then make sure that you do not have any action linked to you power button. Next time you suspend your computer, you'll be able to wake it up by pressing your power button for 6 seconds.