From: Wayne Lin Wayne.Lin@amd.com
stable inclusion from stable-5.10.52 commit 16fb4e9c39b9543efd0c3dbc3dbb8865d090646a bugzilla: 175542 https://gitee.com/openeuler/kernel/issues/I4DTKU
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
--------------------------------
commit 3769e4c0af5b82c8ea21d037013cb9564dfaa51f upstream.
[Why] After unplug/hotplug hub from the system, userspace might start to clear stale payloads gradually. If we call drm_dp_mst_deallocate_vcpi() to release stale VCPI of those ports which are not relating to current topology, we have chane to wrongly clear active payload table entry for current topology.
E.g. We have allocated VCPI 1 in current payload table and we call drm_dp_mst_deallocate_vcpi() to clean VCPI 1 in stale topology. In drm_dp_mst_deallocate_vcpi(), it will call drm_dp_mst_put_payload_id() tp put VCPI 1 and which means ID 1 is available again. Thereafter, if we want to allocate a new payload stream, it will find ID 1 is available by drm_dp_mst_assign_payload_id(). However, ID 1 is being used
[How] Check target sink is relating to current topology or not before doing any payload table update. Searching upward to find the target sink's relevant root branch device. If the found root branch device is not the same root of current topology, don't update payload table.
Changes since v1: * Change debug macro to use drm_dbg_kms() instead * Amend the commit message to add Cc tag.
Signed-off-by: Wayne Lin Wayne.Lin@amd.com Cc: stable@vger.kernel.org Signed-off-by: Lyude Paul lyude@redhat.com Link: https://patchwork.freedesktop.org/patch/msgid/20210616035501.3776-3-Wayne.Li... Reviewed-by: Lyude Paul lyude@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com Signed-off-by: Chen Jun chenjun102@huawei.com --- drivers/gpu/drm/drm_dp_mst_topology.c | 29 +++++++++++++++++++++++++++ 1 file changed, 29 insertions(+)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 702aa0711f80..01570f2549e1 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/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 @@ -3362,6 +3365,7 @@ 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++) { @@ -3376,6 +3380,14 @@ 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 */ @@ -3475,6 +3487,7 @@ 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++) { @@ -3484,6 +3497,13 @@ 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]); @@ -4565,9 +4585,18 @@ 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;