drm/i915: Use atomic helpers for computing changed flags

Replace the drivers own logic for computing mode_changed, active_changed
and planes_changed flags with the check_modeset() atomic helper. Since
that function needs to compare the crtc's new mode with the current,
this patch also moves the set up of crtc_state->mode earlier in the call
chain.

Note that for the call to check_plane() to work properly, we need to
check new plane state against new crtc state. But since we still use the
plane update helper, which doesn't have a full atomic state, we need to
hack around that in intel_plane_atomic_check().
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_atomic_plane.c

@@ -111,6 +111,7 @@ static int intel_plane_atomic_check(struct drm_plane *plane,
 {
 	struct drm_crtc *crtc = state->crtc;
 	struct intel_crtc *intel_crtc;
+	struct intel_crtc_state *crtc_state;
 	struct intel_plane *intel_plane = to_intel_plane(plane);
 	struct intel_plane_state *intel_state = to_intel_plane_state(state);
 
@@ -126,6 +127,17 @@ static int intel_plane_atomic_check(struct drm_plane *plane,
 	if (!crtc)
 		return 0;
 
+	/* FIXME: temporary hack necessary while we still use the plane update
+	 * helper. */
+	if (state->state) {
+		crtc_state =
+			intel_atomic_get_crtc_state(state->state, intel_crtc);
+		if (IS_ERR(crtc_state))
+			return PTR_ERR(crtc_state);
+	} else {
+		crtc_state = intel_crtc->config;
+	}
+
 	/*
 	 * The original src/dest coordinates are stored in state->base, but
 	 * we want to keep another copy internal to our driver that we can
@@ -144,9 +156,9 @@ static int intel_plane_atomic_check(struct drm_plane *plane,
 	intel_state->clip.x1 = 0;
 	intel_state->clip.y1 = 0;
 	intel_state->clip.x2 =
-		intel_crtc->active ? intel_crtc->config->pipe_src_w : 0;
+		crtc_state->base.active ? crtc_state->pipe_src_w : 0;
 	intel_state->clip.y2 =
-		intel_crtc->active ? intel_crtc->config->pipe_src_h : 0;
+		crtc_state->base.active ? crtc_state->pipe_src_h : 0;
 
 	/*
 	 * Disabling a plane is always okay; we just need to update