[PATCH 06/11] drm/amd/display: Add affected crtcs to atomic state for dsc mst unplug

[Jasdeep Dhillon]

From: Roman Li <roman...@amd.com>

[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: ("drm/amd/display: Trigger modesets on MST DSC connectors")

Reviewed-by: Hersen Wu <hersenxs...@amd.com>
Acked-by: Jasdeep Dhillon <jdhil...@amd.com>
Signed-off-by: Roman Li <roman...@amd.com>
---
 drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 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 10ca3fc6d91e..e26217e46c57 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -10851,10 +10851,13 @@ static int dm_check_crtc_cursor(struct 
drm_atomic_state *state,
 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;
 
-- 
2.25.1