From: jsg <jsg@openbsd.org>
Date: Wed, 21 Jul 2021 00:59:32 +0000 (+0000)
Subject: drm/dp_mst: Avoid to mess up payload table by ports in stale topology
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=e6b7af4bd1388fbee944ae75b32f8a63f4463788;p=openbsd

drm/dp_mst: Avoid to mess up payload table by ports in stale topology

From Wayne Lin
16fb4e9c39b9543efd0c3dbc3dbb8865d090646a in linux 5.10.y/5.10.52
3769e4c0af5b82c8ea21d037013cb9564dfaa51f in mainline linux
---

diff --git a/sys/dev/pci/drm/drm_dp_mst_topology.c b/sys/dev/pci/drm/drm_dp_mst_topology.c
index 02ed709b1a0..6d1b4431f89 100644
--- a/sys/dev/pci/drm/drm_dp_mst_topology.c
+++ b/sys/dev/pci/drm/drm_dp_mst_topology.c
@@ -94,6 +94,9 @@ static int drm_dp_mst_register_i2c_bus(struct drm_dp_mst_port *port);
 static void drm_dp_mst_unregister_i2c_bus(struct drm_dp_mst_port *port);
 static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr);
 
+static bool drm_dp_mst_port_downstream_of_branch(struct drm_dp_mst_port *port,
+						 struct drm_dp_mst_branch *branch);
+
 #define DBG_PREFIX "[dp_mst]"
 
 #define DP_STR(x) [DP_ ## x] = #x
@@ -3372,6 +3375,7 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
 	struct drm_dp_mst_port *port;
 	int i, j;
 	int cur_slots = 1;
+	bool skip;
 
 	mutex_lock(&mgr->payload_lock);
 	for (i = 0; i < mgr->max_payloads; i++) {
@@ -3386,6 +3390,14 @@ int drm_dp_update_payload_part1(struct drm_dp_mst_topology_mgr *mgr)
 			port = container_of(vcpi, struct drm_dp_mst_port,
 					    vcpi);
 
+			mutex_lock(&mgr->lock);
+			skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
+			mutex_unlock(&mgr->lock);
+
+			if (skip) {
+				drm_dbg_kms("Virtual channel %d is not in current topology\n", i);
+				continue;
+			}
 			/* Validated ports don't matter if we're releasing
 			 * VCPI
 			 */
@@ -3485,6 +3497,7 @@ int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
 	struct drm_dp_mst_port *port;
 	int i;
 	int ret = 0;
+	bool skip;
 
 	mutex_lock(&mgr->payload_lock);
 	for (i = 0; i < mgr->max_payloads; i++) {
@@ -3494,6 +3507,13 @@ int drm_dp_update_payload_part2(struct drm_dp_mst_topology_mgr *mgr)
 
 		port = container_of(mgr->proposed_vcpis[i], struct drm_dp_mst_port, vcpi);
 
+		mutex_lock(&mgr->lock);
+		skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
+		mutex_unlock(&mgr->lock);
+
+		if (skip)
+			continue;
+
 		DRM_DEBUG_KMS("payload %d %d\n", i, mgr->payloads[i].payload_state);
 		if (mgr->payloads[i].payload_state == DP_PAYLOAD_LOCAL) {
 			ret = drm_dp_create_payload_step2(mgr, port, mgr->proposed_vcpis[i]->vcpi, &mgr->payloads[i]);
@@ -4575,9 +4595,18 @@ EXPORT_SYMBOL(drm_dp_mst_reset_vcpi_slots);
 void drm_dp_mst_deallocate_vcpi(struct drm_dp_mst_topology_mgr *mgr,
 				struct drm_dp_mst_port *port)
 {
+	bool skip;
+
 	if (!port->vcpi.vcpi)
 		return;
 
+	mutex_lock(&mgr->lock);
+	skip = !drm_dp_mst_port_downstream_of_branch(port, mgr->mst_primary);
+	mutex_unlock(&mgr->lock);
+
+	if (skip)
+		return;
+
 	drm_dp_mst_put_payload_id(mgr, port->vcpi.vcpi);
 	port->vcpi.num_slots = 0;
 	port->vcpi.pbn = 0;