drm/amd/display: Add affected crtcs to atomic state for dsc mst unplug

stable inclusion
from stable-v5.10.110
commit 9c384e1afa552c94b5684036d5a26fa6dc11c37e
bugzilla: https://gitee.com/openeuler/kernel/issues/I574AL

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9c384e1afa552c94b5684036d5a26fa6dc11c37e

--------------------------------

[ Upstream commit 128f8ed5 ]

[Why]
When display topology changed on DSC hub we add all crtcs with dsc support to
atomic state.
Refer to patch:"drm/amd/display: Trigger modesets on MST DSC connectors"
However the original implementation may skip crtc if the topology change
caused by unplug.
That potentially could lead to no-lightup or corruption on DSC hub after
unplug event on one of the connectors.

[How]
Update add_affected_mst_dsc_crtcs() to use old connector state
if new connector state has no crtc (undergoes modeset due to unplug)

Fixes: 44be939f ("drm/amd/display: Trigger modesets on MST DSC connectors")
Reviewed-by: NHersen Wu <hersenwu@amd.com>
Acked-by: NJasdeep Dhillon <jdhillon@amd.com>
Signed-off-by: NRoman Li <Roman.Li@amd.com>
Tested-by: NDaniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: NAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: NYu Liao <liaoyu15@huawei.com>
Reviewed-by: NWei Li <liwei391@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

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

@@ -8615,10 +8615,13 @@ static int dm_update_plane_state(struct dc *dc,
 static int add_affected_mst_dsc_crtcs(struct drm_atomic_state *state, struct drm_crtc *crtc)
 {
 	struct drm_connector *connector;
-	struct drm_connector_state *conn_state;
+	struct drm_connector_state *conn_state, *old_conn_state;
 	struct amdgpu_dm_connector *aconnector = NULL;
 	int i;
-	for_each_new_connector_in_state(state, connector, conn_state, i) {
+	for_each_oldnew_connector_in_state(state, connector, old_conn_state, conn_state, i) {
+		if (!conn_state->crtc)
+			conn_state = old_conn_state;
+
 		if (conn_state->crtc != crtc)
 			continue;