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>

diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 6a7078e538e521240981aeb2baee4da8c5a17eee..7d174ba78ebae49032f6e5201e2ebbbee3e6f00a 100644 (file)
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -4848,6 +4848,67 @@ drm_dp_mst_atomic_check_vcpi_alloc_limit(struct drm_dp_mst_topology_mgr *mgr,
        return 0;
 }
 
+/**
+ * drm_dp_mst_add_affected_dsc_crtcs
+ * @state: Pointer to the new struct drm_dp_mst_topology_state
+ * @port: Port pointer of connector with new state
+ *
+ * Whenever there is a change in mst topology
+ * DSC configuration would have to be recalculated
+ * therefore we need to trigger modeset on all affected
+ * CRTCs in that topology
+ *
+ * See also:
+ * drm_dp_mst_atomic_enable_dsc()
+ */
+int drm_dp_mst_add_affected_dsc_crtcs(struct drm_atomic_state *state, struct drm_dp_mst_topology_mgr *mgr)
+{
+       struct drm_dp_mst_topology_state *mst_state;
+       struct drm_dp_vcpi_allocation *pos;
+       struct drm_connector *connector;
+       struct drm_connector_state *conn_state;
+       struct drm_crtc *crtc;
+       struct drm_crtc_state *crtc_state;
+
+       mst_state = drm_atomic_get_mst_topology_state(state, mgr);
+
+       if (IS_ERR(mst_state))
+               return -EINVAL;
+
+       list_for_each_entry(pos, &mst_state->vcpis, next) {
+
+               connector = pos->port->connector;
+
+               if (!connector)
+                       return -EINVAL;
+
+               conn_state = drm_atomic_get_connector_state(state, connector);
+
+               if (IS_ERR(conn_state))
+                       return PTR_ERR(conn_state);
+
+               crtc = conn_state->crtc;
+
+               if (WARN_ON(!crtc))
+                       return -EINVAL;
+
+               if (!drm_dp_mst_dsc_aux_for_port(pos->port))
+                       continue;
+
+               crtc_state = drm_atomic_get_crtc_state(mst_state->base.state, crtc);
+
+               if (IS_ERR(crtc_state))
+                       return PTR_ERR(crtc_state);
+
+               DRM_DEBUG_ATOMIC("[MST MGR:%p] Setting mode_changed flag on CRTC %p\n",
+                                mgr, crtc);
+
+               crtc_state->mode_changed = true;
+       }
+       return 0;
+}
+EXPORT_SYMBOL(drm_dp_mst_add_affected_dsc_crtcs);
+
 /**
  * drm_dp_mst_atomic_enable_dsc - Set DSC Enable Flag to On/Off
  * @state: Pointer to the new drm_atomic_state

diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h
index d940f45c76373e3871e63b47362cece9907d879e..e5503771232fdb9b2327da55d74d47e1519e2ae4 100644 (file)
--- 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);