drm/i915: check connector->encoder before using it.

DP MST will need connectors that aren't connected to specific
encoders, add some checks in advance to avoid oopses.

Reviewed-by: Todd Previte <tprevite@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -2209,13 +2209,15 @@ static void intel_connector_info(struct seq_file *m,
 		seq_printf(m, "\tCEA rev: %d\n",
 			   connector->display_info.cea_rev);
 	}
-	if (intel_encoder->type == INTEL_OUTPUT_DISPLAYPORT ||
-	    intel_encoder->type == INTEL_OUTPUT_EDP)
-		intel_dp_info(m, intel_connector);
-	else if (intel_encoder->type == INTEL_OUTPUT_HDMI)
-		intel_hdmi_info(m, intel_connector);
-	else if (intel_encoder->type == INTEL_OUTPUT_LVDS)
-		intel_lvds_info(m, intel_connector);
+	if (intel_encoder) {
+		if (intel_encoder->type == INTEL_OUTPUT_DISPLAYPORT ||
+		    intel_encoder->type == INTEL_OUTPUT_EDP)
+			intel_dp_info(m, intel_connector);
+		else if (intel_encoder->type == INTEL_OUTPUT_HDMI)
+			intel_hdmi_info(m, intel_connector);
+		else if (intel_encoder->type == INTEL_OUTPUT_LVDS)
+			intel_lvds_info(m, intel_connector);
+	}
 
 	seq_printf(m, "\tmodes:\n");
 	list_for_each_entry(mode, &connector->modes, head)

drivers/gpu/drm/i915/i915_irq.c

@@ -1165,6 +1165,8 @@ static void i915_hotplug_work_func(struct work_struct *work)
 	dev_priv->hpd_event_bits = 0;
 	list_for_each_entry(connector, &mode_config->connector_list, head) {
 		intel_connector = to_intel_connector(connector);
+		if (!intel_connector->encoder)
+			continue;
 		intel_encoder = intel_connector->encoder;
 		if (intel_encoder->hpd_pin > HPD_NONE &&
 		    dev_priv->hpd_stats[intel_encoder->hpd_pin].hpd_mark == HPD_MARK_DISABLED &&
@@ -1195,6 +1197,8 @@ static void i915_hotplug_work_func(struct work_struct *work)
 
 	list_for_each_entry(connector, &mode_config->connector_list, head) {
 		intel_connector = to_intel_connector(connector);
+		if (!intel_connector->encoder)
+			continue;
 		intel_encoder = intel_connector->encoder;
 		if (hpd_event_bits & (1 << intel_encoder->hpd_pin)) {
 			if (intel_encoder->hot_plug)

drivers/gpu/drm/i915/intel_display.c

@@ -5003,20 +5003,23 @@ static void intel_connector_check_state(struct intel_connector *connector)
 		     "wrong connector dpms state\n");
 		WARN(connector->base.encoder != &encoder->base,
 		     "active connector not linked to encoder\n");
-		WARN(!encoder->connectors_active,
-		     "encoder->connectors_active not set\n");
 
-		encoder_enabled = encoder->get_hw_state(encoder, &pipe);
-		WARN(!encoder_enabled, "encoder not enabled\n");
-		if (WARN_ON(!encoder->base.crtc))
-			return;
+		if (encoder) {
+			WARN(!encoder->connectors_active,
+			     "encoder->connectors_active not set\n");
+
+			encoder_enabled = encoder->get_hw_state(encoder, &pipe);
+			WARN(!encoder_enabled, "encoder not enabled\n");
+			if (WARN_ON(!encoder->base.crtc))
+				return;
 
-		crtc = encoder->base.crtc;
+			crtc = encoder->base.crtc;
 
-		WARN(!crtc->enabled, "crtc not enabled\n");
-		WARN(!to_intel_crtc(crtc)->active, "crtc not active\n");
-		WARN(pipe != to_intel_crtc(crtc)->pipe,
-		     "encoder active on the wrong pipe\n");
+			WARN(!crtc->enabled, "crtc not enabled\n");
+			WARN(!to_intel_crtc(crtc)->active, "crtc not active\n");
+			WARN(pipe != to_intel_crtc(crtc)->pipe,
+			     "encoder active on the wrong pipe\n");
+		}
 	}
 }