[Intel-gfx] [PATCH 6/6] drm/i915/dp: Get TC link reference during DP detection

[José Roberto de Souza]

As now the cost to lock and use a TC port is higher due the
implementation of the TCCOLD sequences it is worty to hold a reference
of the TC port to avoid all this locking at every aux transaction
part of the DisplayPort detection.

Cc: Imre Deak <imre.deak at intel.com>
Cc: Cooper Chiou <cooper.chiou at intel.com>
Cc: Kai-Heng Feng <kai.heng.feng at canonical.com>
Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index ef2e06e292d5..89b52211928b 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -5718,6 +5718,7 @@ intel_dp_detect(struct drm_connector *connector,
 	struct intel_dp *intel_dp = intel_attached_dp(to_intel_connector(connector));
 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
 	struct intel_encoder *encoder = &dig_port->base;
+	enum phy phy = intel_port_to_phy(dev_priv, encoder->port);
 	enum drm_connector_status status;
 
 	drm_dbg_kms(&dev_priv->drm, "[CONNECTOR:%d:%s]\n",
@@ -5726,12 +5727,17 @@ intel_dp_detect(struct drm_connector *connector,
 		    !drm_modeset_is_locked(&dev_priv->drm.mode_config.connection_mutex));
 
 	/* Can't disconnect eDP */
-	if (intel_dp_is_edp(intel_dp))
+	if (intel_dp_is_edp(intel_dp)) {
 		status = edp_detect(intel_dp);
-	else if (intel_digital_port_connected(encoder))
-		status = intel_dp_detect_dpcd(intel_dp);
-	else
-		status = connector_status_disconnected;
+	} else {
+		if (intel_phy_is_tc(dev_priv, phy))
+			intel_tc_port_get_link(dig_port, 1);
+
+		if (intel_digital_port_connected(encoder))
+			status = intel_dp_detect_dpcd(intel_dp);
+		else
+			status = connector_status_disconnected;
+	}
 
 	if (status == connector_status_disconnected) {
 		memset(&intel_dp->compliance, 0, sizeof(intel_dp->compliance));
@@ -5809,6 +5815,9 @@ intel_dp_detect(struct drm_connector *connector,
 	if (status != connector_status_connected && !intel_dp->is_mst)
 		intel_dp_unset_edid(intel_dp);
 
+	if (intel_phy_is_tc(dev_priv, phy))
+		intel_tc_port_put_link(dig_port);
+
 	/*
 	 * Make sure the refs for power wells enabled during detect are
 	 * dropped to avoid a new detect cycle triggered by HPD polling.
-- 
2.25.2