South Island (Hainan) and Sea Island (Kaveri) functional with RADV
Running Fedora 28 Design Suite post beta shows a nice surprise: Vulkan with RADV is fully functional on both South Island (Hainan) and Sea Island (Kaveri) cards on ASUS X550ZE laptop. amdgpu driver is needed to enable the feat in combination of boot parameter (cik.amdgpu_support=1 cik.radeon_support=0 si.amdgpu_support=1 si.radeon_support=0)
Vulkan smoketest running on RADV
Some minor issues need be to addressed like occasional glitches. Otherwise the performance is stable enough for dail use.