drm/i915/hdmi: 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_hdmi.c

@@ -43,6 +43,8 @@ struct intel_hdmi {
 	int ddc_bus;
 	bool has_hdmi_sink;
 	bool has_audio;
+	int force_audio;
+	struct drm_property *force_audio_property;
 };
 
 static struct intel_hdmi *enc_to_intel_hdmi(struct drm_encoder *encoder)
@@ -170,6 +172,11 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
 		kfree(edid);
 	}
 
+	if (status == connector_status_connected) {
+		if (intel_hdmi->force_audio)
+			intel_hdmi->has_audio = intel_hdmi->force_audio > 0;
+	}
+
 	return status;
 }
 
@@ -186,6 +193,46 @@ static int intel_hdmi_get_modes(struct drm_connector *connector)
 				   &dev_priv->gmbus[intel_hdmi->ddc_bus].adapter);
 }
 
+static int
+intel_hdmi_set_property(struct drm_connector *connector,
+		      struct drm_property *property,
+		      uint64_t val)
+{
+	struct intel_hdmi *intel_hdmi = intel_attached_hdmi(connector);
+	int ret;
+
+	ret = drm_connector_property_set_value(connector, property, val);
+	if (ret)
+		return ret;
+
+	if (property == intel_hdmi->force_audio_property) {
+		if (val == intel_hdmi->force_audio)
+			return 0;
+
+		intel_hdmi->force_audio = val;
+
+		if (val > 0 && intel_hdmi->has_audio)
+			return 0;
+		if (val < 0 && !intel_hdmi->has_audio)
+			return 0;
+
+		intel_hdmi->has_audio = val > 0;
+		goto done;
+	}
+
+	return -EINVAL;
+
+done:
+	if (intel_hdmi->base.base.crtc) {
+		struct drm_crtc *crtc = intel_hdmi->base.base.crtc;
+		drm_crtc_helper_set_mode(crtc, &crtc->mode,
+					 crtc->x, crtc->y,
+					 crtc->fb);
+	}
+
+	return 0;
+}
+
 static void intel_hdmi_destroy(struct drm_connector *connector)
 {
 	drm_sysfs_connector_remove(connector);
@@ -205,6 +252,7 @@ static const struct drm_connector_funcs intel_hdmi_connector_funcs = {
 	.dpms = drm_helper_connector_dpms,
 	.detect = intel_hdmi_detect,
 	.fill_modes = drm_helper_probe_single_connector_modes,
+	.set_property = intel_hdmi_set_property,
 	.destroy = intel_hdmi_destroy,
 };
 
@@ -218,6 +266,20 @@ static const struct drm_encoder_funcs intel_hdmi_enc_funcs = {
 	.destroy = intel_encoder_destroy,
 };
 
+static void
+intel_hdmi_add_properties(struct intel_hdmi *intel_hdmi, struct drm_connector *connector)
+{
+	struct drm_device *dev = connector->dev;
+
+	intel_hdmi->force_audio_property =
+		drm_property_create(dev, DRM_MODE_PROP_RANGE, "force_audio", 2);
+	if (intel_hdmi->force_audio_property) {
+		intel_hdmi->force_audio_property->values[0] = -1;
+		intel_hdmi->force_audio_property->values[1] = 1;
+		drm_connector_attach_property(connector, intel_hdmi->force_audio_property, 0);
+	}
+}
+
 void intel_hdmi_init(struct drm_device *dev, int sdvox_reg)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -279,6 +341,8 @@ void intel_hdmi_init(struct drm_device *dev, int sdvox_reg)
 
 	drm_encoder_helper_add(&intel_encoder->base, &intel_hdmi_helper_funcs);
 
+	intel_hdmi_add_properties(intel_hdmi, connector);
+
 	intel_connector_attach_encoder(intel_connector, intel_encoder);
 	drm_sysfs_connector_add(connector);