drm/i915: Move long hpd handling into the hotplug work

We can't rely on connector->status in the detect() hook if the long hpd
was already handled by the dig_port_work as that won't update
connector->status. Thus we have to defer the long hpd handling entirely
until the hotplug work runs to avoid the double long hpd handling
the "detect_done" flag is trying to prevent.

We'll start to depend on connector->status being up to date in a
following patch.

Cc: Damien Cassou <damien@cassou.me>
Cc: freedesktop.org@gp.mailgun.org
Cc: Arno <blouin.arno@gmail.com>
Cc: Shubhangi Shrivastava <shubhangi.shrivastava@intel.com>
Cc: Sivakumar Thulasimani <sivakumar.thulasimani@intel.com>
Cc: Ander Conselvan de Oliveira <conselvan2@gmail.com>
Cc: stable@vger.kernel.org
Tested-by: Arno <blouin.arno@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=83348
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1475481316-8194-1-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Ander Conselvan de Oliveira <conselvan2@gmail.com>

drivers/gpu/drm/i915/intel_dp.c

@@ -4827,36 +4827,34 @@ intel_dp_hpd_pulse(struct intel_digital_port *intel_dig_port, bool long_hpd)
 		      port_name(intel_dig_port->port),
 		      long_hpd ? "long" : "short");
 
+	if (long_hpd) {
+		intel_dp->detect_done = false;
+		return IRQ_NONE;
+	}
+
 	power_domain = intel_display_port_aux_power_domain(intel_encoder);
 	intel_display_power_get(dev_priv, power_domain);
 
-	if (long_hpd) {
-		intel_dp_long_pulse(intel_dp->attached_connector);
-		if (intel_dp->is_mst)
-			ret = IRQ_HANDLED;
-		goto put_power;
-
-	} else {
-		if (intel_dp->is_mst) {
-			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) {
+		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);
+			intel_dp->detect_done = false;
+			goto put_power;
 		}
+	}
 
-		if (!intel_dp->is_mst) {
-			if (!intel_dp_short_pulse(intel_dp)) {
-				intel_dp_long_pulse(intel_dp->attached_connector);
-				goto put_power;
-			}
+	if (!intel_dp->is_mst) {
+		if (!intel_dp_short_pulse(intel_dp)) {
+			intel_dp->detect_done = false;
+			goto put_power;
 		}
 	}