Hi all,
Please, read the comments on the AUR package repository in order to find an answer.
‘AUR (en) - opencl-amd-polaris’
You can search in the forum with the words POLARIS10 DRM 3.4.0 in order to find more help.
For example, this post: ‘eGPU issues with external monitor - #28 by pobrn’
Hope this help, regards