[PATCH 5.10 300/599] drm/amd/display: Add affected crtcs to atomic state for dsc mst unplug

From: Greg Kroah-Hartman
Date: Tue Apr 05 2022 - 17:32:22 EST

From: Roman Li <Roman.Li@xxxxxxx>

[ Upstream commit 128f8ed5902a287a6bb4afe0ffdae8a80b2a64ec ]

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.

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@xxxxxxx>
Acked-by: Jasdeep Dhillon <jdhillon@xxxxxxx>
Signed-off-by: Roman Li <Roman.Li@xxxxxxx>
Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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 b65364695219..e828f9414ba2 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/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)