NO LONGER NEEDED for AMD PCI resets...please see https://github.com/gnif/vendor-reset for a working dkms module that fulfills this need.
Due to the architecture of Vega 10 and the lack of appropriate reset code for its built-in PCIe switch, until said reset code exists, one can disable PCIe resets for their Vega card by applying this patch. There appears to be an actual reset patch in the works but no word since last year.
Patch from https://gist.github.com/numinit/1bbabff521e0451e5470d740e0eb82fd
wget https://github.com/torvalds/linux/archive/v4.20.zip
unzip v4.20.zip
git clone https://github.com/netsiphon/vega-reset.git
cd vega-reset/
patch -d ../linux-4.20 -p1 < fix-vega-reset.patch
All hunks must succeed to proceed. If they don't look for the failed hunk and manually correct it if you can.
Please note that the make-custom-kernel script is set to generate 16 threads for the 1700/2700. Choose the appropriate number for an alternate model.
./make-custom-kernel ../linux-4.20 config-4.18.0-13-lowlatency
Restart to use the new kernel