Comment 39 for bug 1453298

I had some patches to improve the vlv rps: http://cgit.freedesktop.org/~ickle/linux-2.6/log/?h=bug88012

They incorporated the change Ben suggested and reduce the number of interrupts required by the manual RPS tuning, as well as making it much more responsive to gfx workload (not that byt has that great a range). It doesn't explain a system hang though...