drm/i915: Introduce encoder->compute_config_late()

Add an optional secondary encoder state compute hook. This gets
called after the normak .compute_config() has been called for
all the encoders in the state. Thus in the new hook we can rely
on all derived state populated by .compute_config() to be already
set up. Should be useful for MST and port sync master/slave
transcoder selection.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200214114126.13192-1-manasi.d.navare@intel.com

drivers/gpu/drm/i915/display/intel_display.c

@@ -13549,6 +13549,35 @@ intel_modeset_pipe_config(struct intel_crtc_state *pipe_config)
 	return 0;
 }
 
+static int
+intel_modeset_pipe_config_late(struct intel_crtc_state *crtc_state)
+{
+	struct intel_atomic_state *state =
+		to_intel_atomic_state(crtc_state->uapi.state);
+	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
+	struct drm_connector_state *conn_state;
+	struct drm_connector *connector;
+	int i;
+
+	for_each_new_connector_in_state(&state->base, connector,
+					conn_state, i) {
+		struct intel_encoder *encoder =
+			to_intel_encoder(conn_state->best_encoder);
+		int ret;
+
+		if (conn_state->crtc != &crtc->base ||
+		    !encoder->compute_config_late)
+			continue;
+
+		ret = encoder->compute_config_late(encoder, crtc_state,
+						   conn_state);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
 bool intel_fuzzy_clock_check(int clock1, int clock2)
 {
 	int diff;
@@ -14954,6 +14983,16 @@ static int intel_atomic_check(struct drm_device *dev,
 		ret = intel_modeset_pipe_config(new_crtc_state);
 		if (ret)
 			goto fail;
+	}
+
+	for_each_oldnew_intel_crtc_in_state(state, crtc, old_crtc_state,
+					    new_crtc_state, i) {
+		if (!needs_modeset(new_crtc_state))
+			continue;
+
+		ret = intel_modeset_pipe_config_late(new_crtc_state);
+		if (ret)
+			goto fail;
 
 		intel_crtc_check_fastset(old_crtc_state, new_crtc_state);
 	}

drivers/gpu/drm/i915/display/intel_display_types.h

@@ -141,6 +141,9 @@ struct intel_encoder {
 	int (*compute_config)(struct intel_encoder *,
 			      struct intel_crtc_state *,
 			      struct drm_connector_state *);
+	int (*compute_config_late)(struct intel_encoder *,
+				   struct intel_crtc_state *,
+				   struct drm_connector_state *);
 	void (*update_prepare)(struct intel_atomic_state *,
 			       struct intel_encoder *,
 			       struct intel_crtc *);