[PATCH 1/2] drm/i915/dp/mst: Fix MST logic in intel_dp_long_pulse()

[Ander Conselvan de Oliveira]

From: "jim.bride at linux.intel.com" <jim.bride at linux.intel.com>

In commit 7d23e3c37bb3 ("drm/i915: Cleaning up intel_dp_hpd_pulse") some
much needed clean-up was done, but unfortunately part of the change
broke DP MST.  The real issue was setting the connector state to
disconnected in the MST case, which is good, but the code then (after
a goto) checks if the connector state is not connected and shuts down
MST if this is the case, which is bad.  With this change both SST and
MST seem to be happy.

v2: Add removed check further up in the function to be sure that MST
    is shut down when we lose the link. (Ander)

Fixes: commit 7d23e3c37bb3 ("drm/i915: Cleaning up intel_dp_hpd_pulse")
cc: Sivakumar Thulasimani <sivakumar.thulasimani at intel.com>
cc: Shubhangi Shrivastava <shubhangi.shrivastava at intel.com>
cc: Ander Conselvan de Oliveira <conselvan2 at gmail.com>
cc: Nathan D Ciobanu <nathan.d.ciobanu at intel.com>
Signed-off-by: Jim Bride <jim.bride at linux.intel.com>
Reviewed-by: Ander Conselvan de Oliveira <conselvan2 at gmail.com>
Reviewed-by: Lyude <cpaul at redhat.com>
Signed-off-by: Ander Conselvan de Oliveira <ander.conselvan.de.oliveira at intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1460394684-7036-1-git-send-email-jim.bride@linux.intel.com
---
 drivers/gpu/drm/i915/intel_dp.c | 24 +++++++++++-------------
 1 file changed, 11 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 61ee226..93d1c48 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -4578,6 +4578,15 @@ intel_dp_long_pulse(struct intel_connector *intel_connector)
 		intel_dp->compliance_test_type = 0;
 		intel_dp->compliance_test_data = 0;
 
+		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);
+		}
+
 		goto out;
 	}
 
@@ -4635,20 +4644,9 @@ intel_dp_long_pulse(struct intel_connector *intel_connector)
 	}
 
 out:
-	if (status != connector_status_connected) {
+	if ((status != connector_status_connected) &&
+	    (intel_dp->is_mst == false))
 		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;
-- 
2.4.11