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

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.