drm/amd/display: Always allocate initial connector state state

[Why]
Unlike our regular connectors, MST connectors don't start off with
an initial connector state. This causes a NULL pointer dereference to
occur when attaching the bpc property since it tries to modify the
connector state.

We need an initial connector state on the connector to avoid the crash.

[How]
Use our reset helper to allocate an initial state and reset the values
to their defaults. We were already doing this before, just not for
MST connectors.

Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.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 d8947fe5117c1b6dc2fb9d5fec9191dc3d0fbf67..d3c39ff6d7e272fb390779fc797ee5a7b9ebefaa 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -4778,6 +4778,13 @@ void amdgpu_dm_connector_init_helper(struct amdgpu_display_manager *dm,
 {
        struct amdgpu_device *adev = dm->ddev->dev_private;
 
+       /*
+        * Some of the properties below require access to state, like bpc.
+        * Allocate some default initial connector state with our reset helper.
+        */
+       if (aconnector->base.funcs->reset)
+               aconnector->base.funcs->reset(&aconnector->base);
+
        aconnector->connector_id = link_index;
        aconnector->dc_link = link;
        aconnector->base.interlace_allowed = false;
@@ -4967,9 +4974,6 @@ static int amdgpu_dm_connector_init(struct amdgpu_display_manager *dm,
                        &aconnector->base,
                        &amdgpu_dm_connector_helper_funcs);
 
-       if (aconnector->base.funcs->reset)
-               aconnector->base.funcs->reset(&aconnector->base);
-
        amdgpu_dm_connector_init_helper(
                dm,
                aconnector,