FAILED: patch "[PATCH] drm/dp/mst: split connector registration into two parts (v2)" failed to apply to 4.2-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.2-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From d9515c5ec1a20c77d83471e634ad9bb12deb0eac Mon Sep 17 00:00:00 2001
From: Dave Airlie <airlied@redhat.com>
Date: Wed, 16 Sep 2015 17:55:23 +1000
Subject: [PATCH] drm/dp/mst: split connector registration into two parts (v2)

In order to cache the EDID properly for tiled displays, we
need to retrieve it before we register the connector with
userspace, otherwise userspace can call get resources
and try and get the edid before we've even cached it.

This fixes some problems when hotplugging mst monitors,
with X/mutter running. As mutter seems to get 0 modes
for one of the monitors in the tile.

v2: fix warning in radeon
handle tile setting in cached path rather than
get edid path.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index a2f5caaee242..36454a146ae9 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -1129,7 +1129,9 @@ static void drm_dp_add_port(struct drm_dp_mst_branch *mstb,
 		}
 		if (port->port_num >= 8) {
 			port->cached_edid = drm_get_edid(port->connector, &port->aux.ddc);
+			drm_mode_connector_set_tile_property(port->connector);
 		}
+		(*mstb->mgr->cbs->register_connector)(port->connector);
 	}
 
 out:
@@ -2276,10 +2278,10 @@ struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_
 
 	if (port->cached_edid)
 		edid = drm_edid_duplicate(port->cached_edid);
-	else
+	else {
 		edid = drm_get_edid(connector, &port->aux.ddc);
-
-	drm_mode_connector_set_tile_property(connector);
+		drm_mode_connector_set_tile_property(connector);
+	}
 	drm_dp_put_port(port);
 	return edid;
 }
diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
index 3e4be5a3becd..6ade06888432 100644
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -462,11 +462,17 @@ static struct drm_connector *intel_dp_add_mst_connector(struct drm_dp_mst_topolo
 	drm_object_attach_property(&connector->base, dev->mode_config.tile_property, 0);
 
 	drm_mode_connector_set_path_property(connector, pathprop);
+	return connector;
+}
+
+static void intel_dp_register_mst_connector(struct drm_connector *connector)
+{
+	struct intel_connector *intel_connector = to_intel_connector(connector);
+	struct drm_device *dev = connector->dev;
 	drm_modeset_lock_all(dev);
 	intel_connector_add_to_fbdev(intel_connector);
 	drm_modeset_unlock_all(dev);
 	drm_connector_register(&intel_connector->base);
-	return connector;
 }
 
 static void intel_dp_destroy_mst_connector(struct drm_dp_mst_topology_mgr *mgr,
@@ -512,6 +518,7 @@ static void intel_dp_mst_hotplug(struct drm_dp_mst_topology_mgr *mgr)
 
 static struct drm_dp_mst_topology_cbs mst_cbs = {
 	.add_connector = intel_dp_add_mst_connector,
+	.register_connector = intel_dp_register_mst_connector,
 	.destroy_connector = intel_dp_destroy_mst_connector,
 	.hotplug = intel_dp_mst_hotplug,
 };
diff --git a/drivers/gpu/drm/radeon/radeon_dp_mst.c b/drivers/gpu/drm/radeon/radeon_dp_mst.c
index 5e09c061847f..6cddae44fa6e 100644
--- a/drivers/gpu/drm/radeon/radeon_dp_mst.c
+++ b/drivers/gpu/drm/radeon/radeon_dp_mst.c
@@ -265,7 +265,6 @@ static struct drm_connector *radeon_dp_add_mst_connector(struct drm_dp_mst_topol
 {
 	struct radeon_connector *master = container_of(mgr, struct radeon_connector, mst_mgr);
 	struct drm_device *dev = master->base.dev;
-	struct radeon_device *rdev = dev->dev_private;
 	struct radeon_connector *radeon_connector;
 	struct drm_connector *connector;
 
@@ -286,12 +285,19 @@ static struct drm_connector *radeon_dp_add_mst_connector(struct drm_dp_mst_topol
 	drm_object_attach_property(&connector->base, dev->mode_config.path_property, 0);
 	drm_mode_connector_set_path_property(connector, pathprop);
 
+	return connector;
+}
+
+static void radeon_dp_register_mst_connector(struct drm_connector *connector)
+{
+	struct drm_device *dev = connector->dev;
+	struct radeon_device *rdev = dev->dev_private;
+
 	drm_modeset_lock_all(dev);
 	radeon_fb_add_connector(rdev, connector);
 	drm_modeset_unlock_all(dev);
 
 	drm_connector_register(connector);
-	return connector;
 }
 
 static void radeon_dp_destroy_mst_connector(struct drm_dp_mst_topology_mgr *mgr,
@@ -324,6 +330,7 @@ static void radeon_dp_mst_hotplug(struct drm_dp_mst_topology_mgr *mgr)
 
 struct drm_dp_mst_topology_cbs mst_cbs = {
 	.add_connector = radeon_dp_add_mst_connector,
+	.register_connector = radeon_dp_register_mst_connector,
 	.destroy_connector = radeon_dp_destroy_mst_connector,
 	.hotplug = radeon_dp_mst_hotplug,
 };
diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
index 86d0b25ed054..0f408b002d98 100644
--- a/include/drm/drm_dp_mst_helper.h
+++ b/include/drm/drm_dp_mst_helper.h
@@ -374,6 +374,7 @@ struct drm_dp_mst_topology_mgr;
 struct drm_dp_mst_topology_cbs {
 	/* create a connector for a port */
 	struct drm_connector *(*add_connector)(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, const char *path);
+	void (*register_connector)(struct drm_connector *connector);
 	void (*destroy_connector)(struct drm_dp_mst_topology_mgr *mgr,
 				  struct drm_connector *connector);
 	void (*hotplug)(struct drm_dp_mst_topology_mgr *mgr);