Commit 9dcf67de authored by Imre Deak's avatar Imre Deak
Browse files

drm/dp_mst: Add helper to determine if an MST port is downstream of another port 



Add drm_dp_mst_port_downstream_of_parent() required by the i915
driver in a follow-up patch to resolve a BW overallocation of MST
streams going through a given MST port.

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/20231030155843.2251023-4-imre.deak@intel.com
parent 7707dd60

drivers/gpu/drm/display/drm_dp_mst_topology.c

+52 −0
Original line number Diff line number Diff line
@@ -5126,6 +5126,58 @@ static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port, 
	return false;

}



static bool

drm_dp_mst_port_downstream_of_parent_locked(struct drm_dp_mst_topology_mgr *mgr,

					    struct drm_dp_mst_port *port,

					    struct drm_dp_mst_port *parent)

{

	if (!mgr->mst_primary)

		return false;



	port = drm_dp_mst_topology_get_port_validated_locked(mgr->mst_primary,

							     port);

	if (!port)

		return false;



	if (!parent)

		return true;



	parent = drm_dp_mst_topology_get_port_validated_locked(mgr->mst_primary,

							       parent);

	if (!parent)

		return false;



	if (!parent->mstb)

		return false;



	return drm_dp_mst_port_downstream_of_branch(port, parent->mstb);

}



/**

 * drm_dp_mst_port_downstream_of_parent - check if a port is downstream of a parent port

 * @mgr: MST topology manager

 * @port: the port being looked up

 * @parent: the parent port

 *

 * The function returns %true if @port is downstream of @parent. If @parent is

 * %NULL - denoting the root port - the function returns %true if @port is in

 * @mgr's topology.

 */

bool

drm_dp_mst_port_downstream_of_parent(struct drm_dp_mst_topology_mgr *mgr,

				     struct drm_dp_mst_port *port,

				     struct drm_dp_mst_port *parent)

{

	bool ret;



	mutex_lock(&mgr->lock);

	ret = drm_dp_mst_port_downstream_of_parent_locked(mgr, port, parent);

	mutex_unlock(&mgr->lock);



	return ret;

}

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);

include/drm/display/drm_dp_mst_helper.h

+3 −0
Original line number Diff line number Diff line
@@ -892,6 +892,9 @@ drm_atomic_get_new_mst_topology_state(struct drm_atomic_state *state, 
struct drm_dp_mst_atomic_payload *

drm_atomic_get_mst_payload_state(struct drm_dp_mst_topology_state *state,

				 struct drm_dp_mst_port *port);

bool drm_dp_mst_port_downstream_of_parent(struct drm_dp_mst_topology_mgr *mgr,

					  struct drm_dp_mst_port *port,

					  struct drm_dp_mst_port *parent);

int __must_check

drm_dp_atomic_find_time_slots(struct drm_atomic_state *state,

			      struct drm_dp_mst_topology_mgr *mgr,