Commit 1cd0a5ea authored by Imre Deak's avatar Imre Deak
Browse files

drm/dp_mst: Factor out a helper to check the atomic state of a topology manager 



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@redhat.com>
Cc: dri-devel@lists.freedesktop.org
Reviewed-by: default avatarLyude Paul <lyude@redhat.com>
Acked-by: default avatarMaxime Ripard <mripard@kernel.org>
Signed-off-by: default avatarImre Deak <imre.deak@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231030155843.2251023-5-imre.deak@intel.com
parent 9dcf67de

drivers/gpu/drm/display/drm_dp_mst_topology.c

+74 −19
Original line number Diff line number Diff line
@@ -5180,11 +5180,13 @@ 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;
@@ -5213,7 +5215,7 @@ 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;
@@ -5225,7 +5227,8 @@ 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;
@@ -5246,13 +5249,15 @@ 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;

	}
@@ -5261,6 +5266,7 @@ 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;

	}
@@ -5438,20 +5444,79 @@ 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()

 *
@@ -5466,21 +5531,11 @@ 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;

include/drm/display/drm_dp_mst_helper.h

+4 −0
Original line number Diff line number Diff line
@@ -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);