(In reply to comment #60)
> Instead of triggering the power level switches by running GpuTest in bursts,
> I put this in a bash script:
> 
> for i in {1..3600}
> do
>    echo low > /sys/class/drm/card0/device/power_dpm_force_performance_level
>    sleep 1
>    echo high > /sys/class/drm/card0/device/power_dpm_force_performance_level
>    sleep 5
> done
> 
> and just let GpuTest, and piglit, run continously. I found that this also
> trigger the lockups within minutes.
> 
> Then I ran the script by itself, no GpuTest or piglit, and left it running
> while I was at work. When I came home the machine was still running, so it
> ran for six hours without any lockup. So it seems the power level switching
> alone is not sufficient to trigger the lockups, it also needs a load of some
> sort.

Do you mean while spread spectrum is still enabled?