Factor out a helper to check the atomic state for one MST topology
manager, returning the MST port where the BW limit check has failed.
This will be used in a follow-up patch by the i915 driver to improve the
BW sharing between MST streams.
Cc: Lyude Paul <lyude@xxxxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Reviewed-by: Lyude Paul <lyude@xxxxxxxxxx>
Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
---
drivers/gpu/drm/display/drm_dp_mst_topology.c | 93 +++++++++++++++----
include/drm/display/drm_dp_mst_helper.h | 4 +
2 files changed, 78 insertions(+), 19 deletions(-)
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index 22a901493d24c..3d93bc093c46c 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -5190,11 +5190,13 @@ EXPORT_SYMBOL(drm_dp_mst_port_downstream_of_parent);
static int
drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
- struct drm_dp_mst_topology_state *state);
+ struct drm_dp_mst_topology_state *state,
+ struct drm_dp_mst_port **failing_port);
static int
drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb,
- struct drm_dp_mst_topology_state *state)
+ struct drm_dp_mst_topology_state *state,
+ struct drm_dp_mst_port **failing_port)
{
struct drm_dp_mst_atomic_payload *payload;
struct drm_dp_mst_port *port;
@@ -5223,7 +5225,7 @@ drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb,
drm_dbg_atomic(mstb->mgr->dev, "[MSTB:%p] Checking bandwidth limits\n", mstb);
list_for_each_entry(port, &mstb->ports, next) {
- ret = drm_dp_mst_atomic_check_port_bw_limit(port, state);
+ ret = drm_dp_mst_atomic_check_port_bw_limit(port, state, failing_port);
if (ret < 0)
return ret;
@@ -5235,7 +5237,8 @@ drm_dp_mst_atomic_check_mstb_bw_limit(struct drm_dp_mst_branch *mstb,
static int
drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
- struct drm_dp_mst_topology_state *state)
+ struct drm_dp_mst_topology_state *state,
+ struct drm_dp_mst_port **failing_port)
{
struct drm_dp_mst_atomic_payload *payload;
int pbn_used = 0;
@@ -5256,13 +5259,15 @@ drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
drm_dbg_atomic(port->mgr->dev,
"[MSTB:%p] [MST PORT:%p] no BW available for the port\n",
port->parent, port);
+ *failing_port = port;
return -EINVAL;
}
pbn_used = payload->pbn;
} else {
pbn_used = drm_dp_mst_atomic_check_mstb_bw_limit(port->mstb,
- state);
+ state,
+ failing_port);
if (pbn_used <= 0)
return pbn_used;
}
@@ -5271,6 +5276,7 @@ drm_dp_mst_atomic_check_port_bw_limit(struct drm_dp_mst_port *port,
drm_dbg_atomic(port->mgr->dev,
"[MSTB:%p] [MST PORT:%p] required PBN of %d exceeds port limit of %d\n",
port->parent, port, pbn_used, port->full_pbn);
+ *failing_port = port;
return -ENOSPC;
}
@@ -5448,20 +5454,79 @@ int drm_dp_mst_atomic_enable_dsc(struct drm_atomic_state *state,
}
EXPORT_SYMBOL(drm_dp_mst_atomic_enable_dsc);
+/**
+ * drm_dp_mst_atomic_check_mgr - Check the atomic state of an MST topology manager
+ * @state: The global atomic state
+ * @mgr: Manager to check
+ * @mst_state: The MST atomic state for @mgr
+ * @failing_port: Returns the port with a BW limitation
+ *
+ * Checks the given MST manager's topology state for an atomic update to ensure
+ * that it's valid. This includes checking whether there's enough bandwidth to
+ * support the new timeslot allocations in the atomic update.
+ *
+ * Any atomic drivers supporting DP MST must make sure to call this or
+ * the drm_dp_mst_atomic_check() function after checking the rest of their state
+ * in their &drm_mode_config_funcs.atomic_check() callback.
+ *
+ * See also:
+ * drm_dp_mst_atomic_check()
+ * drm_dp_atomic_find_time_slots()
+ * drm_dp_atomic_release_time_slots()
+ *
+ * Returns:
+ * - 0 if the new state is valid
+ * - %-ENOSPC, if the new state is invalid, because of BW limitation
+ * @failing_port is set to:
+ * - The non-root port where a BW limit check failed
+ * The returned port pointer is valid until at least
+ * one payload downstream of it exists.
+ * - %NULL if the BW limit check failed at the root port
+ * - %-EINVAL, if the new state is invalid, because the root port has
+ * too many payloads.
+ */
+int drm_dp_mst_atomic_check_mgr(struct drm_atomic_state *state,
+ struct drm_dp_mst_topology_mgr *mgr,
+ struct drm_dp_mst_topology_state *mst_state,
+ struct drm_dp_mst_port **failing_port)
+{
+ int ret;
+
+ *failing_port = NULL;
+
+ if (!mgr->mst_state)
+ return 0;
+
+ ret = drm_dp_mst_atomic_check_payload_alloc_limits(mgr, mst_state);
+ if (ret)
+ return ret;
+
+ mutex_lock(&mgr->lock);
+ ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary,
+ mst_state,
+ failing_port);
+ mutex_unlock(&mgr->lock);
+
+ return ret < 0 ? ret : 0;
+}
+EXPORT_SYMBOL(drm_dp_mst_atomic_check_mgr);
+
/**
* drm_dp_mst_atomic_check - Check that the new state of an MST topology in an
* atomic update is valid
* @state: Pointer to the new &struct drm_dp_mst_topology_state
*
* Checks the given topology state for an atomic update to ensure that it's
- * valid. This includes checking whether there's enough bandwidth to support
- * the new timeslot allocations in the atomic update.
+ * valid, calling drm_dp_mst_atomic_check_mgr() for all MST manager in the
+ * atomic state. This includes checking whether there's enough bandwidth to
+ * support the new timeslot allocations in the atomic update.
*
* Any atomic drivers supporting DP MST must make sure to call this after
* checking the rest of their state in their
* &drm_mode_config_funcs.atomic_check() callback.
*
* See also:
+ * drm_dp_mst_atomic_check_mgr()
* drm_dp_atomic_find_time_slots()
* drm_dp_atomic_release_time_slots()
*
@@ -5476,21 +5541,11 @@ int drm_dp_mst_atomic_check(struct drm_atomic_state *state)
int i, ret = 0;
for_each_new_mst_mgr_in_state(state, mgr, mst_state, i) {
- if (!mgr->mst_state)
- continue;
+ struct drm_dp_mst_port *tmp_port;
- ret = drm_dp_mst_atomic_check_payload_alloc_limits(mgr, mst_state);
+ ret = drm_dp_mst_atomic_check_mgr(state, mgr, mst_state, &tmp_port);
if (ret)
break;
-
- mutex_lock(&mgr->lock);
- ret = drm_dp_mst_atomic_check_mstb_bw_limit(mgr->mst_primary,
- mst_state);
- mutex_unlock(&mgr->lock);
- if (ret < 0)
- break;
- else
- ret = 0;
}
return ret;
diff --git a/include/drm/display/drm_dp_mst_helper.h b/include/drm/display/drm_dp_mst_helper.h
index aecce52cae167..0e570b67563b5 100644
--- a/include/drm/display/drm_dp_mst_helper.h
+++ b/include/drm/display/drm_dp_mst_helper.h
@@ -916,6 +916,10 @@ int drm_dp_send_power_updown_phy(struct drm_dp_mst_topology_mgr *mgr,
int drm_dp_send_query_stream_enc_status(struct drm_dp_mst_topology_mgr *mgr,
struct drm_dp_mst_port *port,
struct drm_dp_query_stream_enc_status_ack_reply *status);
+int __must_check drm_dp_mst_atomic_check_mgr(struct drm_atomic_state *state,
+ struct drm_dp_mst_topology_mgr *mgr,
+ struct drm_dp_mst_topology_state *mst_state,
+ struct drm_dp_mst_port **failing_port);
int __must_check drm_dp_mst_atomic_check(struct drm_atomic_state *state);
int __must_check drm_dp_mst_root_conn_atomic_check(struct drm_connector_state *new_conn_state,
struct drm_dp_mst_topology_mgr *mgr);
--
2.37.2
