drm/i915: Cleaning up intel_dp_hpd_pulse

Current DP detection has DPCD operations split across
intel_dp_hpd_pulse and intel_dp_detect which contains
duplicates as well. Also intel_dp_detect is called
during modes enumeration as well which will result
in multiple dpcd operations. So this patch tries
to solve both these by bringing all DPCD operations
in one single function and make intel_dp_detect
use existing values instead of repeating same steps.

v2: Pulled in a hunk from last patch of the series to
    this patch. (Ander)

v3: Added MST hotplug handling. (Ander)

v4: Added a flag to check if detect is performed to
    prevent multiple detects on hotplug. (Ander)

Tested-by: Nathan D Ciobanu <nathan.d.ciobanu@intel.com>
Signed-off-by: Sivakumar Thulasimani <sivakumar.thulasimani@intel.com>
Signed-off-by: Shubhangi Shrivastava <shubhangi.shrivastava@intel.com>
Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com>
[anderco: fix parenthesis aligment]
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1459341326-13142-2-git-send-email-shubhangi.shrivastava@intel.com

drivers/gpu/drm/i915/intel_dp.c

@@ -4582,6 +4582,16 @@ intel_dp_long_pulse(struct intel_connector *intel_connector)
 		 */
 		status = connector_status_disconnected;
 		goto out;
+	} else if (connector->status == connector_status_connected) {
+		/*
+		 * If display was connected already and is still connected
+		 * check links status, there has been known issues of
+		 * link loss triggerring long pulse!!!!
+		 */
+		drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
+		intel_dp_check_link_status(intel_dp);
+		drm_modeset_unlock(&dev->mode_config.connection_mutex);
+		goto out;
 	}
 
 	/*
@@ -4595,6 +4605,7 @@ intel_dp_long_pulse(struct intel_connector *intel_connector)
 	intel_dp_set_edid(intel_dp);
 
 	status = connector_status_connected;
+	intel_dp->detect_done = true;
 
 	/* Try to read the source of the interrupt */
 	if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11 &&
@@ -4611,8 +4622,21 @@ intel_dp_long_pulse(struct intel_connector *intel_connector)
 	}
 
 out:
-	if (status != connector_status_connected)
+	if (status != connector_status_connected) {
 		intel_dp_unset_edid(intel_dp);
+		/*
+		 * If we were in MST mode, and device is not there,
+		 * get out of MST mode
+		 */
+		if (intel_dp->is_mst) {
+			DRM_DEBUG_KMS("MST device may have disappeared %d vs %d\n",
+				      intel_dp->is_mst, intel_dp->mst_mgr.mst_state);
+			intel_dp->is_mst = false;
+			drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr,
+							intel_dp->is_mst);
+		}
+	}
+
 	intel_display_power_put(to_i915(dev), power_domain);
 	return;
 }
@@ -4636,7 +4660,11 @@ intel_dp_detect(struct drm_connector *connector, bool force)
 		return connector_status_disconnected;
 	}
 
-	intel_dp_long_pulse(intel_dp->attached_connector);
+	/* If full detect is not performed yet, do a full detect */
+	if (!intel_dp->detect_done)
+		intel_dp_long_pulse(intel_dp->attached_connector);
+
+	intel_dp->detect_done = false;
 
 	if (intel_connector->detect_edid)
 		return connector_status_connected;
@@ -4968,25 +4996,25 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
 		/* indicate that we need to restart link training */
 		intel_dp->train_set_valid = false;
 
-		if (!intel_digital_port_connected(dev_priv, intel_dig_port))
-			goto mst_fail;
-
-		if (!intel_dp_get_dpcd(intel_dp)) {
-			goto mst_fail;
-		}
-
-		intel_dp_probe_oui(intel_dp);
+		intel_dp_long_pulse(intel_dp->attached_connector);
+		if (intel_dp->is_mst)
+			ret = IRQ_HANDLED;
+		goto put_power;
 
-		if (!intel_dp_probe_mst(intel_dp)) {
-			drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
-			intel_dp_check_link_status(intel_dp);
-			drm_modeset_unlock(&dev->mode_config.connection_mutex);
-			goto mst_fail;
-		}
 	} else {
 		if (intel_dp->is_mst) {
-			if (intel_dp_check_mst_status(intel_dp) == -EINVAL)
-				goto mst_fail;
+			if (intel_dp_check_mst_status(intel_dp) == -EINVAL) {
+				/*
+				 * If we were in MST mode, and device is not
+				 * there, get out of MST mode
+				 */
+				DRM_DEBUG_KMS("MST device may have disappeared %d vs %d\n",
+					      intel_dp->is_mst, intel_dp->mst_mgr.mst_state);
+				intel_dp->is_mst = false;
+				drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr,
+								intel_dp->is_mst);
+				goto put_power;
+			}
 		}
 
 		if (!intel_dp->is_mst) {
@@ -4998,14 +5026,6 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
 
 	ret = IRQ_HANDLED;
 
-	goto put_power;
-mst_fail:
-	/* if we were in MST mode, and device is not there get out of MST mode */
-	if (intel_dp->is_mst) {
-		DRM_DEBUG_KMS("MST device may have disappeared %d vs %d\n", intel_dp->is_mst, intel_dp->mst_mgr.mst_state);
-		intel_dp->is_mst = false;
-		drm_dp_mst_topology_mgr_set_mst(&intel_dp->mst_mgr, intel_dp->is_mst);
-	}
 put_power:
 	intel_display_power_put(dev_priv, power_domain);
 

drivers/gpu/drm/i915/intel_drv.h

@@ -797,6 +797,7 @@ struct intel_dp {
 	int link_rate;
 	uint8_t lane_count;
 	bool has_audio;
+	bool detect_done;
 	enum hdmi_force_audio force_audio;
 	bool limited_color_range;
 	bool color_range_auto;