Thanks for the report. This had a Vega specific fix in mind but I guess it extends to Polaris as well. I would imagine the first patch from this thread should fix your issue (ie. the one that's *not* the dce120 one) https://bugzilla.kernel.org/show_bug.cgi?id=201067 If it doesn't, then you should post your full dmesg and Xorg logs.