https://bugs.freedesktop.org/show_bug.cgi?id=69723
--- Comment #68 from Martin Andersson g02maran@gmail.com --- It seems I also spoke to soon, because I tried again with mclk disabled but this time with the test method where I forced the low and high power levels by using /sys/class/drm/card0/device/power_dpm_force_performance_level and this time I got a lockup.
So either it was just chance that I didn't hit the lockup with mclk disabled the first time and/or my second test method have a higher chance of triggering the lockup.
I'm currently running a test with dynamic_ss disabled.