[PATCH 12/29] drm/i915: Filter out glitches during hotplug detection

[Imre Deak]

Signed-off-by: Imre Deak <imre.deak at intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 58063686acfe5..b9487afe0f09f 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -5484,11 +5484,21 @@ bool intel_digital_port_connected(struct intel_encoder *encoder)
 {
 	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
 	struct intel_digital_port *dig_port = enc_to_dig_port(encoder);
+	enum phy phy = intel_port_to_phy(dev_priv, dig_port->base.port);
+	bool is_tc_port = intel_phy_is_tc(dev_priv, phy);
 	bool is_connected = false;
 	intel_wakeref_t wakeref;
 
-	with_intel_display_power(dev_priv, POWER_DOMAIN_DISPLAY_CORE, wakeref)
-		is_connected = dig_port->connected(encoder);
+	with_intel_display_power(dev_priv, POWER_DOMAIN_DISPLAY_CORE, wakeref) {
+		unsigned long wait_expires = jiffies + msecs_to_jiffies_timeout(4);
+
+		do {
+			is_connected = dig_port->connected(encoder);
+			if (is_connected || is_tc_port)
+				break;
+			udelay(30);
+		} while (time_before(jiffies, wait_expires));
+	}
 
 	return is_connected;
 }
-- 
2.39.2