I have now completed a 12+ hour long test run with dynamic_ss disabled (mclk_ss
was also disable) without any problem. So it seems that disabling mclk_ss makes
it a little more stable, but disabling dynamic_ss makes it much more stable. I
have not had any lockups with dynamic_ss disabled, but I haven't tested it that
much. Only this long session and one 6+ hour long session before that.

The next thing I'm gonna test is dynamic_ss disabled and the patches from
https://bugs.freedesktop.org/show_bug.cgi?id=68235 reverted.