[PATCH 1/2] drm/i915: HDMI detection based on HPD pin live status

[Ramalingam C <ramalingam.c@intel.com>]

This change uses the HPD pins live status bit from
South Display Engine(SDE) to identify the HDMI hotplug state.

On Soft HPD events (on automated test cases) only HPD pin will be
toggled to notify the HDMI state change. But physical DDC will
be alive. Similarly on slow HDMI hotplug out, because of the physical
interface design, DDC remains active for short duration even when
HPD live status is indicating the disconnect state. Because of this
on VLV and HSW, slow hotplug out events and soft HPDs are not captured.

Hence this patch uses the HPD pins live status to identify the
HDMI connector status and allows EDID retrival only when live status
is up.

Change-Id: I958b57fa139e52b45c8b349c861cb8eab7b67ae5
Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
---
 drivers/gpu/drm/i915/intel_drv.h  |   10 +++++
 drivers/gpu/drm/i915/intel_hdmi.c |   87 ++++++++++++++++++++++++++++++++-----
 2 files changed, 85 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 46aea6c..0f7d94b 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -444,6 +444,16 @@ struct cxsr_latency {
 #define to_intel_framebuffer(x) container_of(x, struct intel_framebuffer, base)
 #define to_intel_plane(x) container_of(x, struct intel_plane, base)
 
+/* DisplayPort/HDMI Hotplug line status bit mask */
+#define VLV_HDMIB_HOTPLUG_LIVE_STATUS   (1 << 29)
+#define VLV_HDMIC_HOTPLUG_LIVE_STATUS   (1 << 28)
+#define VLV_HDMID_HOTPLUG_LIVE_STATUS   (1 << 27)
+
+/* DisplayPort/HDMI/DVI Hotplug line status bit mask */
+#define CORE_HDMIB_HOTPLUG_LIVE_STATUS  (1 << 21)
+#define CORE_HDMIC_HOTPLUG_LIVE_STATUS  (1 << 22)
+#define CORE_HDMID_HOTPLUG_LIVE_STATUS  (1 << 23)
+
 struct intel_hdmi {
 	u32 hdmi_reg;
 	int ddc_bus;
diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
index 6db0d9d..faeae3a 100644
--- a/drivers/gpu/drm/i915/intel_hdmi.c
+++ b/drivers/gpu/drm/i915/intel_hdmi.c
@@ -924,6 +924,61 @@ bool intel_hdmi_compute_config(struct intel_encoder *encoder,
 	return true;
 }
 
+static int get_hdmi_hotplug_live_status(struct drm_device *dev,
+					struct intel_hdmi *intel_hdmi)
+{
+	uint32_t bit, reg;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_digital_port *intel_dig_port =
+				hdmi_to_dig_port(intel_hdmi);
+
+	DRM_DEBUG_KMS("Reading Live status");
+
+	/* Live status is available from Gen 6 onwards */
+	if (INTEL_INFO(dev)->gen < 6)
+		return connector_status_connected;
+
+	if (IS_VALLEYVIEW(dev)) {
+		switch (intel_dig_port->port) {
+		case PORT_B:
+			bit = VLV_HDMIB_HOTPLUG_LIVE_STATUS;
+			break;
+		case PORT_C:
+			bit = VLV_HDMIC_HOTPLUG_LIVE_STATUS;
+			break;
+		case PORT_D:
+			bit = VLV_HDMID_HOTPLUG_LIVE_STATUS;
+			break;
+		default:
+			DRM_ERROR("Unrecognized port is encountered\n");
+			return connector_status_unknown;
+		}
+		reg = I915_READ(PORT_HOTPLUG_STAT);
+
+	} else {
+		switch (intel_dig_port->port) {
+		case PORT_B:
+			bit = CORE_HDMIB_HOTPLUG_LIVE_STATUS;
+			break;
+		case PORT_C:
+			bit = CORE_HDMIC_HOTPLUG_LIVE_STATUS;
+			break;
+		case PORT_D:
+			bit = CORE_HDMID_HOTPLUG_LIVE_STATUS;
+			break;
+		default:
+			DRM_ERROR("Unrecognized port is encountered\n");
+			return connector_status_unknown;
+		}
+
+		reg = I915_READ(SDEISR);
+	}
+
+	/* Return connector status */
+	return ((reg & bit) ?
+		connector_status_connected : connector_status_disconnected);
+}
+
 static enum drm_connector_status
 intel_hdmi_detect(struct drm_connector *connector, bool force)
 {
@@ -939,24 +994,32 @@ intel_hdmi_detect(struct drm_connector *connector, bool force)
 	DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n",
 		      connector->base.id, drm_get_connector_name(connector));
 
+	status = get_hdmi_hotplug_live_status(dev, intel_hdmi);
+
 	intel_hdmi->has_hdmi_sink = false;
 	intel_hdmi->has_audio = false;
 	intel_hdmi->rgb_quant_range_selectable = false;
-	edid = drm_get_edid(connector,
-			    intel_gmbus_get_adapter(dev_priv,
-						    intel_hdmi->ddc_bus));
 
-	if (edid) {
-		if (edid->input & DRM_EDID_INPUT_DIGITAL) {
-			status = connector_status_connected;
-			if (intel_hdmi->force_audio != HDMI_AUDIO_OFF_DVI)
-				intel_hdmi->has_hdmi_sink =
+	if (status == connector_status_connected) {
+		edid = drm_get_edid(connector,
+				intel_gmbus_get_adapter(dev_priv,
+						intel_hdmi->ddc_bus));
+		if (edid) {
+			if (edid->input & DRM_EDID_INPUT_DIGITAL) {
+				status = connector_status_connected;
+				if (intel_hdmi->force_audio !=
+							HDMI_AUDIO_OFF_DVI)
+					intel_hdmi->has_hdmi_sink =
 						drm_detect_hdmi_monitor(edid);
-			intel_hdmi->has_audio = drm_detect_monitor_audio(edid);
-			intel_hdmi->rgb_quant_range_selectable =
-				drm_rgb_quant_range_selectable(edid);
+				intel_hdmi->has_audio =
+						drm_detect_monitor_audio(edid);
+				intel_hdmi->rgb_quant_range_selectable =
+					drm_rgb_quant_range_selectable(edid);
+			}
+			kfree(edid);
+		} else {
+			status = connector_status_disconnected;
 		}
-		kfree(edid);
 	}
 
 	if (status == connector_status_connected) {
-- 
1.7.9.5