drm/dp_mst: Add helper to trigger modeset on affected DSC MST CRTCs

[why]
Whenever a connector on an MST network is changed or
undergoes a modeset, the DSC configs for each stream on that
topology will be recalculated. This can change their required
bandwidth, requiring a full reprogramming, as though a modeset
was performed, even if that stream did not change timing.

[how]
Adding helper to trigger modesets on MST DSC connectors
by setting mode_changed flag on CRTCs in the same topology
as affected connector

v2: use drm_dp_mst_dsc_aux_for_port function to verify
if the port is DSC capable

v3: - added _must_check attribute
    - removed topology manager check
    - fix typos and indentations

Reviewed-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
index d940f45c7637..e5503771232f 100644
--- a/include/drm/drm_dp_mst_helper.h
+++ b/include/drm/drm_dp_mst_helper.h
@@ -788,6 +788,9 @@ int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
 				 int pbn, int pbn_div,
 				 bool enable);
 int __must_check
+drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state,
+				  struct drm_dp_mst_topology_mgr *mgr);
+int __must_check
 drm_dp_atomic_release_vcpi_slots(struct drm_atomic_state *state,
 				 struct drm_dp_mst_topology_mgr *mgr,
 				 struct drm_dp_mst_port *port);