g the
drm_helper-specific crtc and encoder dpms functions, automatically computing
the appropriate DPMS level for each object in the system.

This fixes the current troubles in the i915 driver which left PLLs, pipes
and planes running while in DPMS_OFF mode or even while they were unused.

Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
d&v