I used to suspend/resume my system on Ubuntu 17.04 and it was fine. I installed
Ubuntu 17.10 that comes with Linux 4.13 and now my system cannot wake-up
anymore.

I submitted the bug on Ubuntu's web site. I tried Linux 4.14 but the problem
was still present. Then I've been told to open a bug here.

The original bug: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1720622

/var/log/kern.log shows several errors regarding amdgpu.

My RX 480 is connected to one single screen with DisplayPort. The problem
occurs with both wayland and xorg.