drm/i915: Avoid concurrent access when marking the device as idle/busy

As suggested by Daniel, rip out the independent timers for device and
crtc busyness and integrate the manual powermanagement of the display
engine into the GEM core and its request tracking. The benefits are that
the code is a lot smaller, fewer moving parts and should fit more neatly
into the overall activity tracking of the driver.

v2: Complete overhaul and removal of the racy timers and workers.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 2846f5e..8c7f483 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -156,8 +156,6 @@
 	int dpms_mode;
 	bool active; /* is the crtc on? independent of the dpms mode */
 	bool primary_disabled; /* is the crtc obscured by a plane? */
-	bool busy; /* is scanout buffer being updated frequently? */
-	struct timer_list idle_timer;
 	bool lowfreq_avail;
 	struct intel_overlay *overlay;
 	struct intel_unpin_work *unpin_work;
@@ -373,8 +371,10 @@
 			    bool is_sdvob);
 extern void intel_dvo_init(struct drm_device *dev);
 extern void intel_tv_init(struct drm_device *dev);
-extern void intel_mark_busy(struct drm_device *dev,
-			    struct drm_i915_gem_object *obj);
+extern void intel_mark_busy(struct drm_device *dev);
+extern void intel_mark_idle(struct drm_device *dev);
+extern void intel_mark_fb_busy(struct drm_i915_gem_object *obj);
+extern void intel_mark_fb_idle(struct drm_i915_gem_object *obj);
 extern bool intel_lvds_init(struct drm_device *dev);
 extern void intel_dp_init(struct drm_device *dev, int output_reg,
 			  enum port port);