[Bug 29842] Radeon runs very hot

[Phillip Susi]

So I have been looking over the source code in drivers/gpu/drm/radeon.
I see various functions to start/stop/resume/initialize "mc" and "cp".
I assume those stand for microcode and control program?  What exactly is
the difference?

It seems like the GPU is executing a few different microcode kernels
that process commands placed into ring buffers.  When the ring buffers
are empty and the gui is idle, it seems like the GPU is still busily
executing an infinite loop checking for work in the ring buffers.
Shouldn't the driver detect the idle condition and issue an
r600_cp_stop() to halt execution and stop wasting power?