drm/amd/display: Only register backlight device if embedded panel connected

Signed-off-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 33 insertions, 25 deletions

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 e42a28e3adc5..54bf0b39c38b 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1403,6 +1403,28 @@ static int initialize_plane(struct amdgpu_display_manager *dm,
         return ret;
 }
 
+
+static void register_backlight_device(struct amdgpu_display_manager *dm,
+                                      struct dc_link *link)
+{
+#if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) ||\
+        defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
+
+        if ((link->connector_signal & (SIGNAL_TYPE_EDP | SIGNAL_TYPE_LVDS)) &&
+            link->type != dc_connection_none) {
+                /* Event if registration failed, we should continue with
+                 * DM initialization because not having a backlight control
+                 * is better then a black screen.
+                 */
+                amdgpu_dm_register_backlight_device(dm);
+
+                if (dm->backlight_dev)
+                        dm->backlight_link = link;
+        }
+#endif
+}
+
+
 /* In this architecture, the association
  * connector -> encoder -> crtc
  * id not really requried. The crtc and connector will hold the
@@ -1456,6 +1478,7 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
 
         /* loops over all connectors on the board */
         for (i = 0; i < link_cnt; i++) {
+                struct dc_link *link = NULL;
 
                 if (i > AMDGPU_DM_MAX_DISPLAY_INDEX) {
                         DRM_ERROR(
@@ -1482,9 +1505,14 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
                         goto fail;
                 }
 
-                if (dc_link_detect(dc_get_link_at_index(dm->dc, i),
-                                DETECT_REASON_BOOT))
+                link = dc_get_link_at_index(dm->dc, i);
+
+                if (dc_link_detect(link, DETECT_REASON_BOOT)) {
                         amdgpu_dm_update_connector_after_detect(aconnector);
+                        register_backlight_device(dm, link);
+                }
+
+
         }
 
         /* Software is initialized. Now we can register interrupt handlers. */
@@ -2685,7 +2713,8 @@ static void amdgpu_dm_connector_destroy(struct drm_connector *connector)
 #if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) ||\
         defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
 
-        if (link->connector_signal & (SIGNAL_TYPE_EDP | SIGNAL_TYPE_LVDS)) {
+        if ((link->connector_signal & (SIGNAL_TYPE_EDP | SIGNAL_TYPE_LVDS)) &&
+            link->type != dc_connection_none) {
                 amdgpu_dm_register_backlight_device(dm);
 
                 if (dm->backlight_dev) {
@@ -3561,6 +3590,7 @@ create_i2c(struct ddc_service *ddc_service,
         return i2c;
 }
 
+
 /* Note: this function assumes that dc_link_detect() was called for the
  * dc_link which will be represented by this aconnector.
  */
@@ -3630,28 +3660,6 @@ static int amdgpu_dm_connector_init(struct amdgpu_display_manager *dm,
                 || connector_type == DRM_MODE_CONNECTOR_eDP)
                 amdgpu_dm_initialize_dp_connector(dm, aconnector);
 
-#if defined(CONFIG_BACKLIGHT_CLASS_DEVICE) ||\
-        defined(CONFIG_BACKLIGHT_CLASS_DEVICE_MODULE)
-
-        /* NOTE: this currently will create backlight device even if a panel
-         * is not connected to the eDP/LVDS connector.
-         *
-         * This is less than ideal but we don't have sink information at this
-         * stage since detection happens after. We can't do detection earlier
-         * since MST detection needs connectors to be created first.
-         */
-        if (link->connector_signal & (SIGNAL_TYPE_EDP | SIGNAL_TYPE_LVDS)) {
-                /* Event if registration failed, we should continue with
-                 * DM initialization because not having a backlight control
-                 * is better then a black screen.
-                 */
-                amdgpu_dm_register_backlight_device(dm);
-
-                if (dm->backlight_dev)
-                        dm->backlight_link = link;
-        }
-#endif
-
 out_free:
         if (res) {
                 kfree(i2c);