From b89fdf7ae8500feae1100d8b283176a44d31d698 Mon Sep 17 00:00:00 2001
From: Lyude Paul <lyude@redhat.com>
Date: Wed, 14 Nov 2018 20:39:51 -0500
Subject: drm/nouveau/drm/nouveau: Check rc from
 drm_dp_mst_topology_mgr_resume()
Git-commit: b89fdf7ae8500feae1100d8b283176a44d31d698
Patch-mainline: v5.0-rc1
References: bsc#1113956

We need to actually make sure we check this on resume since otherwise we
won't know whether or not the topology is still there once we've
resumed, which will cause us to still think the topology is connected
even after it's been removed if the removal happens mid-suspend.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 drivers/gpu/drm/nouveau/dispnv50/disp.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index 6cbbae3f438b..6aa3521b6326 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -1255,8 +1255,16 @@ nv50_mstm_fini(struct nv50_mstm *mstm)
 static void
 nv50_mstm_init(struct nv50_mstm *mstm)
 {
-	if (mstm && mstm->mgr.mst_state)
-		drm_dp_mst_topology_mgr_resume(&mstm->mgr);
+	int ret;
+
+	if (!mstm || !mstm->mgr.mst_state)
+		return;
+
+	ret = drm_dp_mst_topology_mgr_resume(&mstm->mgr);
+	if (ret == -1) {
+		drm_dp_mst_topology_mgr_set_mst(&mstm->mgr, false);
+		drm_kms_helper_hotplug_event(mstm->mgr.dev);
+	}
 }
 
 static void
-- 
2.20.1