drm/amdgpu: Don't ignore rc from drm_dp_mst_topology_mgr_resume()

drm_dp_mst_topology_mgr_resume() returns whether or not it managed to
find the topology in question after a suspend resume cycle, and the
driver is supposed to check this value and disable MST accordingly if
it's gone-in addition to sending a hotplug in order to notify userspace
that something changed during suspend.

Currently, amdgpu just makes the mistake of ignoring the return code
from drm_dp_mst_topology_mgr_resume() which means that if a topology was
removed in suspend, amdgpu never notices and assumes it's still
connected which leads to all sorts of problems.

So, fix this by actually checking the rc from
drm_dp_mst_topology_mgr_resume(). Also, reformat the rest of the
function while we're at it to fix the over-indenting.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Cc: Jerry Zuo <Jerry.Zuo@amd.com>
Cc: <stable@vger.kernel.org> # v4.15+
Link: https://patchwork.freedesktop.org/patch/msgid/20190108211133.32564-2-lyude@redhat.com

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index a9a28dbc3e2421e36468554a554d1987b7c4f46e..127b1e8f58e6bf324d03847f7cedc8e1a08aef16 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -699,22 +699,36 @@ static void s3_handle_mst(struct drm_device *dev, bool suspend)
 {
        struct amdgpu_dm_connector *aconnector;
        struct drm_connector *connector;
+       struct drm_dp_mst_topology_mgr *mgr;
+       int ret;
+       bool need_hotplug = false;
 
        drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
 
-       list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
-                  aconnector = to_amdgpu_dm_connector(connector);
-                  if (aconnector->dc_link->type == dc_connection_mst_branch &&
-                                  !aconnector->mst_port) {
+       list_for_each_entry(connector, &dev->mode_config.connector_list,
+                           head) {
+               aconnector = to_amdgpu_dm_connector(connector);
+               if (aconnector->dc_link->type != dc_connection_mst_branch ||
+                   aconnector->mst_port)
+                       continue;
+
+               mgr = &aconnector->mst_mgr;
 
-                          if (suspend)
-                                  drm_dp_mst_topology_mgr_suspend(&aconnector->mst_mgr);
-                          else
-                                  drm_dp_mst_topology_mgr_resume(&aconnector->mst_mgr);
-                  }
+               if (suspend) {
+                       drm_dp_mst_topology_mgr_suspend(mgr);
+               } else {
+                       ret = drm_dp_mst_topology_mgr_resume(mgr);
+                       if (ret < 0) {
+                               drm_dp_mst_topology_mgr_set_mst(mgr, false);
+                               need_hotplug = true;
+                       }
+               }
        }
 
        drm_modeset_unlock(&dev->mode_config.connection_mutex);
+
+       if (need_hotplug)
+               drm_kms_helper_hotplug_event(dev);
 }
 
 /**