This linux AMD Forum may help you find an answer if you can't find one from here: https://www.phoronix.com/forums/forum/linux-graphics-x-org-drivers/amd-linux
Don't know if this website on Mint Linux 18.3 may help or not. Installing AMDGPU-PRO in 18.3 breaks graphics - Linux Mint Forums
How to install latest AMD Drivers in Bionic Ubuntu: https://linuxconfig.org/how-to-install-the-latest-amd-radeon-drivers-on-ubuntu-18-04-bionic-beaver-linux
thanks for the links, they definitely make an interesting read!
According to what I have been able to find on the phoronix forums, the --px switch
worked until amdgpu-pro version 17.x. I checked the driver content, and indeed, the
xserver modesetting package does exist in there.
In the amdgpu-pro driver versions 18.20 / 18.30 for ubuntu 18.04 the package is missing, though.
Which then results in the installer error.
Thisis somewhat sad, as the switch is even better documented than before in
the new amdgpu-pro 18.30 documentation at:
Does anybody have a switchable graphics system in production use
for OpenCl usage?
Is the missing package even necessary?
I wrote a bugreport for amdgpu-pro as suggested by the documentation
for amdgpu-pro on linux, version 18.30, at the bugzilla/freedesktop site.
In addition, I notified the AMD customer care about the missing file in the driver
archive. I am not sure about the reception, though... I do hope
they passed it on to the technical support.
Would there be something else I can do in order to make the issue known & fixed?