drm/i915: skylake panel fitting using shared scalers

Enabling skylake panel fitting feature using shared scalers

v2:
-added force detach parameter for pfit disable purpose (me)
-read crtc scaler state from hw state (Daniel)
-replaced both skylake_pfit_enable and disable with skylake_pfit_update (me)
-added scaler id check to intel_pipe_config_compare (Daniel)

v3:
-updated function header to kerneldoc format (Matt)
-dropped need_scaling checks (Matt)

v4:
-move clearing of scaler id from commit path to check path (Matt)
-updated colorkey checks based on recent updates (me)
-squashed scaler check while enabling colorkey to here (me)
-use values in plane_state->src as regular integers (me)
-changes made not to modify state in commit path (Matt)

v5:
-squashed helper function to update scaler users to here (Matt)
-squashed helper function to detach scaler to here (Matt, me)
-changes to align with updated scaler structures (Matt, me)
Signed-off-by: Chandra Konduru <chandra.konduru@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_dp.c

@@ -1351,6 +1351,14 @@ intel_dp_compute_config(struct intel_encoder *encoder,
 	if (is_edp(intel_dp) && intel_connector->panel.fixed_mode) {
 		intel_fixed_panel_mode(intel_connector->panel.fixed_mode,
 				       adjusted_mode);
+
+		if (INTEL_INFO(dev)->gen >= 9) {
+			int ret;
+			ret = skl_update_scaler_users(intel_crtc, pipe_config, NULL, NULL, 0);
+			if (ret)
+				return ret;
+		}
+
 		if (!HAS_PCH_SPLIT(dev))
 			intel_gmch_panel_fitting(intel_crtc, pipe_config,
 						 intel_connector->panel.fitting_mode);

drivers/gpu/drm/i915/intel_drv.h

@@ -1128,6 +1128,10 @@ void intel_mode_from_pipe_config(struct drm_display_mode *mode,
 				 struct intel_crtc_state *pipe_config);
 void intel_crtc_wait_for_pending_flips(struct drm_crtc *crtc);
 void intel_modeset_preclose(struct drm_device *dev, struct drm_file *file);
+void skl_detach_scalers(struct intel_crtc *intel_crtc);
+int skl_update_scaler_users(struct intel_crtc *intel_crtc,
+	struct intel_crtc_state *crtc_state, struct intel_plane *intel_plane,
+	struct intel_plane_state *plane_state, int force_detach);
 
 unsigned long intel_plane_obj_offset(struct intel_plane *intel_plane,
 				     struct drm_i915_gem_object *obj);