[Intel-gfx] [PATCH 2/6] drm/i915: Cleaning up intel_dp_hpd_pulse

[Shubhangi Shrivastava]

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)

Tested-by: Nathan D Ciobanu <nathan.d.ciobanu at intel.com>
Signed-off-by: Sivakumar Thulasimani <sivakumar.thulasimani at intel.com>
Signed-off-by: Shubhangi Shrivastava <shubhangi.shrivastava at intel.com>
---
 drivers/gpu/drm/i915/intel_dp.c | 71 +++++++++++++++++++++++++----------------
 1 file changed, 44 insertions(+), 27 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index e3b4208..137757b 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4645,8 +4645,19 @@ intel_dp_long_pulse(struct intel_connector *intel_connector)
 	intel_dp_probe_oui(intel_dp);
 
 	ret = intel_dp_probe_mst(intel_dp);
-	if (ret)
+	if (ret) {
+		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;
+	}
 
 	/*
 	 * Clearing NACK and defer counts to get their exact values
@@ -4677,8 +4688,21 @@ 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;
 }
@@ -4701,7 +4725,8 @@ intel_dp_detect(struct drm_connector *connector, bool force)
 		return connector_status_disconnected;
 	}
 
-	intel_dp_long_pulse(intel_dp->attached_connector);
+	if (force)
+		intel_dp_long_pulse(intel_dp->attached_connector);
 
 	if (intel_connector->detect_edid)
 		return connector_status_connected;
@@ -5034,25 +5059,25 @@ 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) {
@@ -5064,14 +5089,6 @@ 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);
 
-- 
2.6.1