This is on a fresh install of Ubuntu 16.04.2 LTS. All of the latest OS updates have been downloaded and installed.
Without the AMDGPU-PRO 17.10 driver, shutdown and reboot works fine via both GUI or shell.
But after I installed the AMDGPU-PRO driver, shutdown and reboot will hang with monitor going to standby (same as the video cable is disconnected or PC is powered off). But the PC is still powered on, the fans are spinning. Remove the AMDGPU-PRO driver, then things are working again. Therefore, I am sure the problem is caused by the driver.
If I look at all the shutdown log messages, the last message is "Reached target shutdown" so it has clearly reached the next-to-final step, except it doesn't power off the PC like it should.
Is there a solution for this?