drm/amd/display: Fix dmesg warning from setting abm level

[Why]
Setting abm level does not correctly update CRTC state. As a result
no surface update is added to dc stream state and triggers warning.

[How]
Correctly update CRTC state when setting abm level property.

CC: Stable <stable@vger.kernel.org>
Signed-off-by: Stylon Wang <stylon.wang@amd.com>
Reviewed-by: Nicholas Kazlauskas <Nicholas.Kazlauskas@amd.com>
Acked-by: Eryk Brol <eryk.brol@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -8656,6 +8656,29 @@ static int amdgpu_dm_atomic_check(struct drm_device *dev,
 	if (ret)
 		goto fail;
 
+	/* Check connector changes */
+	for_each_oldnew_connector_in_state(state, connector, old_con_state, new_con_state, i) {
+		struct dm_connector_state *dm_old_con_state = to_dm_connector_state(old_con_state);
+		struct dm_connector_state *dm_new_con_state = to_dm_connector_state(new_con_state);
+
+		/* Skip connectors that are disabled or part of modeset already. */
+		if (!old_con_state->crtc && !new_con_state->crtc)
+			continue;
+
+		if (!new_con_state->crtc)
+			continue;
+
+		new_crtc_state = drm_atomic_get_crtc_state(state, new_con_state->crtc);
+		if (IS_ERR(new_crtc_state)) {
+			ret = PTR_ERR(new_crtc_state);
+			goto fail;
+		}
+
+		if (dm_old_con_state->abm_level !=
+		    dm_new_con_state->abm_level)
+			new_crtc_state->connectors_changed = true;
+	}
+
 #if defined(CONFIG_DRM_AMD_DC_DCN)
 	if (adev->asic_type >= CHIP_NAVI10) {
 		for_each_oldnew_crtc_in_state(state, crtc, old_crtc_state, new_crtc_state, i) {