The following commands from comment #239 seems to have corrected the issue on
my Raden HD3650 Mobility:

>> echo high > /sys/class/drm/card0/device/power_dpm_force_performance_level
>> echo performance > /sys/class/drm/card0/device/power_dpm_state

This seems to be equivalent to the patch in comment #244. Any chance of getting
this patch into the kernel?

If anyone is willing to write a fix, as opposed to a workaround, for this
issue, I would be happy to test it on my device.