Problem on HP probook 450, with Radeon R7 M260/M265.
Please see:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1589379

To sum-up:
- before commit 4474b85771139f2da8f8f4f443e6fad08081e99e, resume was working OK
(version 4.4.3)
- from commit 4474b85771139f2da8f8f4f443e6fad08081e99e (drm/amdgpu: remove exp
hardware support from iceland), I cannot boot on the OS (version 4.4.4)
- from commit 53e609099daa023ad7771ec8351202f2a7bee1c1 (drm/amdgpu: fix
topaz/tonga gmc assignment in 4.4 stable), I can boot into the OS and see the
problem of system frozen on resume (this bug report)(version 4.4.5 and above).