drm/i915: Add an update_pipe callback to intel_encoder and call this on fastsets (v2)

When we are doing a fastset (needs_modeset=false, update_pipe=true) we
may need to update some encoder-level things such as checking that PSR
is enabled.

This commit adds an update_pipe callback to intel_encoder and a new
intel_encoders_update_pipe helper which calls this for all encoders
connected to a crtc. The new intel_encoders_update_pipe helper is called
from intel_update_crtc when doing a fastset.

Changes in v2:
-Name the new encoder callback update_pipe instead of just update
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181220132120.15318-1-hdegoede@redhat.com

drivers/gpu/drm/i915/intel_display.c

@@ -5578,6 +5578,26 @@ static void intel_encoders_post_pll_disable(struct drm_crtc *crtc,
 	}
 }
 
+static void intel_encoders_update_pipe(struct drm_crtc *crtc,
+				       struct intel_crtc_state *crtc_state,
+				       struct drm_atomic_state *old_state)
+{
+	struct drm_connector_state *conn_state;
+	struct drm_connector *conn;
+	int i;
+
+	for_each_new_connector_in_state(old_state, conn, conn_state, i) {
+		struct intel_encoder *encoder =
+			to_intel_encoder(conn_state->best_encoder);
+
+		if (conn_state->crtc != crtc)
+			continue;
+
+		if (encoder->update_pipe)
+			encoder->update_pipe(encoder, crtc_state, conn_state);
+	}
+}
+
 static void ironlake_crtc_enable(struct intel_crtc_state *pipe_config,
 				 struct drm_atomic_state *old_state)
 {
@@ -12750,6 +12770,9 @@ static void intel_update_crtc(struct drm_crtc *crtc,
 	} else {
 		intel_pre_plane_update(to_intel_crtc_state(old_crtc_state),
 				       pipe_config);
+
+		if (pipe_config->update_pipe)
+			intel_encoders_update_pipe(crtc, pipe_config, state);
 	}
 
 	if (pipe_config->update_pipe && !pipe_config->enable_fbc)

drivers/gpu/drm/i915/intel_drv.h

@@ -243,6 +243,9 @@ struct intel_encoder {
 	void (*post_pll_disable)(struct intel_encoder *,
 				 const struct intel_crtc_state *,
 				 const struct drm_connector_state *);
+	void (*update_pipe)(struct intel_encoder *,
+			    const struct intel_crtc_state *,
+			    const struct drm_connector_state *);
 	/* Read out the current hw state of this connector, returning true if
 	 * the encoder is active. If the encoder is enabled it also set the pipe
 	 * it is connected to in the pipe parameter. */