(In reply to comment #62)
> What are rings 1 and rings 2 ? I suspect one of the ring is the constant
> engine but I'm not sure if it's currently supported or not.
> 

1 and 2 are compute rings.  The constant engine is part of the gfx ring.

> I've read that hawaii has something a gfx/compute command queue and 7
> compute only command queue, does they use the same ring ?

The gfx ring can execute gfx or compute work.  There are many compute rings on
CI hardware, but we currently only expose two.