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

[ Upstream commit 128f8ed5902a287a6bb4afe0ffdae8a80b2a64ec ]

[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: 44be939ff7ac58 ("drm/amd/display: Trigger modesets on MST DSC connectors")

Reviewed-by: Hersen Wu <hersenwu@amd.com>
Acked-by: Jasdeep Dhillon <jdhillon@amd.com>
Signed-off-by: Roman Li <Roman.Li@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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 7983c01..b9859e5 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -10226,10 +10226,13 @@ 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;