Created attachment 139556 [details]
the dmesg output

WHAT HAPPENS
- Amdgpu refuses to start without any information as of why.
- The problem happened between Ubuntu 17.10 and Ubuntu 18.04
- Three behaviors are occurring:
  a) The login happens normally (very rare, only 2 times)
  b) The login fails, the screen remain stuck and nothing happens
  c) The login fails and I am sent back to the login screen
- The mouse cursor does not respond to movements.
- I can access to the console via Ctrl+Alt F4
- The "dmesg" output is in attachment. The smoking gun in my opinion is
[  170.244044] [drm:atom_op_jump [amdgpu]] *ERROR* atombios stuck in loop for more than 5secs aborting

TIPS
- I can access to login screen and to all the data on the computer. But only in text mode. So I can update 

The crashes that allows ssh connection almost always happens when firefox is openned and running a video (netflix, youtube) or whatsapp web.
- The crashes that simply hangs the entire computer may occur at any time.

OBSERVATIONS
- No modification were done to the driver, only standard driver from ubuntu 18.04.

SYSTEM SPECS
- Dell Inspiron 5767 is used. Kernel from Ubuntu