drm/i915/sdvo: Add 'force_audio' property

Allow the user to override the detection of the sink's audio capabilities
from EDID. Not all sinks support the required EDID level to specify
whether they handle audio over the display connection, so allow the user
to enable it manually.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drivers/gpu/drm/i915/intel_sdvo.c

@@ -107,6 +107,7 @@ struct intel_sdvo {
 	 * This is set if we treat the device as HDMI, instead of DVI.
 	 */
 	bool is_hdmi;
+	bool has_audio;
 
 	/**
 	 * This is set if we detect output of sdvo device as LVDS and
@@ -138,11 +139,15 @@ struct intel_sdvo_connector {
 	/* Mark the type of connector */
 	uint16_t output_flag;
 
+	int force_audio;
+
 	/* This contains all current supported TV format */
 	u8 tv_format_supported[TV_FORMAT_NUM];
 	int   format_supported_num;
 	struct drm_property *tv_format;
 
+	struct drm_property *force_audio_property;
+
 	/* add the property for the SDVO-TV */
 	struct drm_property *left;
 	struct drm_property *right;
@@ -1150,7 +1155,7 @@ static void intel_sdvo_mode_set(struct drm_encoder *encoder,
 	}
 	if (intel_crtc->pipe == 1)
 		sdvox |= SDVO_PIPE_B_SELECT;
-	if (intel_sdvo->is_hdmi)
+	if (intel_sdvo->has_audio)
 		sdvox |= SDVO_AUDIO_ENABLE;
 
 	if (INTEL_INFO(dev)->gen >= 4) {
@@ -1476,11 +1481,18 @@ intel_sdvo_hdmi_sink_detect(struct drm_connector *connector)
 		if (edid->input & DRM_EDID_INPUT_DIGITAL) {
 			status = connector_status_connected;
 			intel_sdvo->is_hdmi = drm_detect_hdmi_monitor(edid);
+			intel_sdvo->has_audio = drm_detect_monitor_audio(edid);
 		}
 		connector->display_info.raw_edid = NULL;
 		kfree(edid);
 	}
-	
+
+	if (status == connector_status_connected) {
+		struct intel_sdvo_connector *intel_sdvo_connector = to_intel_sdvo_connector(connector);
+		if (intel_sdvo_connector->force_audio)
+			intel_sdvo->has_audio = intel_sdvo_connector->force_audio > 0;
+	}
+
 	return status;
 }
 
@@ -1787,6 +1799,21 @@ intel_sdvo_set_property(struct drm_connector *connector,
 	if (ret)
 		return ret;
 
+	if (property == intel_sdvo_connector->force_audio_property) {
+		if (val == intel_sdvo_connector->force_audio)
+			return 0;
+
+		intel_sdvo_connector->force_audio = val;
+
+		if (val > 0 && intel_sdvo->has_audio)
+			return 0;
+		if (val < 0 && !intel_sdvo->has_audio)
+			return 0;
+
+		intel_sdvo->has_audio = val > 0;
+		goto done;
+	}
+
 #define CHECK_PROPERTY(name, NAME) \
 	if (intel_sdvo_connector->name == property) { \
 		if (intel_sdvo_connector->cur_##name == temp_value) return 0; \
@@ -2078,6 +2105,21 @@ intel_sdvo_connector_init(struct intel_sdvo_connector *connector,
 	drm_sysfs_connector_add(&connector->base.base);
 }
 
+static void
+intel_sdvo_add_hdmi_properties(struct intel_sdvo_connector *connector)
+{
+	struct drm_device *dev = connector->base.base.dev;
+
+	connector->force_audio_property =
+		drm_property_create(dev, DRM_MODE_PROP_RANGE, "force_audio", 2);
+	if (connector->force_audio_property) {
+		connector->force_audio_property->values[0] = -1;
+		connector->force_audio_property->values[1] = 1;
+		drm_connector_attach_property(&connector->base.base,
+					      connector->force_audio_property, 0);
+	}
+}
+
 static bool
 intel_sdvo_dvi_init(struct intel_sdvo *intel_sdvo, int device)
 {
@@ -2118,6 +2160,8 @@ intel_sdvo_dvi_init(struct intel_sdvo *intel_sdvo, int device)
 
 	intel_sdvo_connector_init(intel_sdvo_connector, intel_sdvo);
 
+	intel_sdvo_add_hdmi_properties(intel_sdvo_connector);
+
 	return true;
 }