drm/i915: always update ELD connector type after get modes

drm_edid_to_eld() initializes the connector ELD to zero, overwriting the
ELD connector type initialized in intel_audio_codec_enable(). If
userspace does getconnector and thus get_modes after modeset, a
subsequent audio component i915_audio_component_get_eld() call will
receive an ELD without the connector type properly set. It's fine for
HDMI, but screws up audio for DP.

Always set the ELD connector type at intel_connector_update_modes()
based on the connector type. We can drop the connector type update from
intel_audio_codec_enable().

Credits to Joseph Nuzman <jnuzman@gmail.com> for figuring this out.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Joseph Nuzman <jnuzman@gmail.com>
Reported-by: Joseph Nuzman <jnuzman@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=101583
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: Joseph Nuzman <jnuzman@gmail.com>
Cc: stable@vger.kernel.org # v4.10+, maybe earlier
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170919153813.29808-1-jani.nikula@intel.com

drivers/gpu/drm/i915/intel_audio.c

@@ -606,11 +606,6 @@ void intel_audio_codec_enable(struct intel_encoder *intel_encoder,
 			 connector->encoder->base.id,
 			 connector->encoder->name);
 
-	/* ELD Conn_Type */
-	connector->eld[5] &= ~(3 << 2);
-	if (intel_crtc_has_dp_encoder(crtc_state))
-		connector->eld[5] |= (1 << 2);
-
 	connector->eld[6] = drm_av_sync_delay(connector, adjusted_mode) / 2;
 
 	if (dev_priv->display.audio_codec_enable)

drivers/gpu/drm/i915/intel_modes.c

@@ -30,6 +30,21 @@
 #include "intel_drv.h"
 #include "i915_drv.h"
 
+static void intel_connector_update_eld_conn_type(struct drm_connector *connector)
+{
+	u8 conn_type;
+
+	if (connector->connector_type == DRM_MODE_CONNECTOR_DisplayPort ||
+	    connector->connector_type == DRM_MODE_CONNECTOR_eDP) {
+		conn_type = DRM_ELD_CONN_TYPE_DP;
+	} else {
+		conn_type = DRM_ELD_CONN_TYPE_HDMI;
+	}
+
+	connector->eld[DRM_ELD_SAD_COUNT_CONN_TYPE] &= ~DRM_ELD_CONN_TYPE_MASK;
+	connector->eld[DRM_ELD_SAD_COUNT_CONN_TYPE] |= conn_type;
+}
+
 /**
  * intel_connector_update_modes - update connector from edid
  * @connector: DRM connector device to use
@@ -44,6 +59,8 @@ int intel_connector_update_modes(struct drm_connector *connector,
 	ret = drm_add_edid_modes(connector, edid);
 	drm_edid_to_eld(connector, edid);
 
+	intel_connector_update_eld_conn_type(connector);
+
 	return ret;
 }