Thanks all for adding comments and testing to this bug. I believe if we prove
there is enough people affected on different cards, it will get the attention
it needs, and hopefully a permanent mesa fix can be found and implemented.

For those affected, if you don't mind testing the kernel parameters workaround
i described above, and post your results, that would be a nice start.
If you need help on how to do that you can reach out to me via PM or email.