From: Kurt Kanzenbach The Multi-queue Priority (MQPRIO) and Earliest TxTime First (ETF) offloads utilize the Time Sensitive Networking (TSN) Tx mode. This mode is always coupled to IEEE 802.1Qbv time aware shaper (Qbv). Therefore, the driver sets a default Qbv schedule of all gates opened and a cycle time of 1s. This schedule is set during probe. However, the following sequence of events lead to Tx issues: - Boot a dual core system igc_probe(): igc_tsn_clear_schedule(): -> Default Schedule is set Note: At this point the driver has allocated two Tx/Rx queues, because there are only two CPUs. - ethtool -L enp3s0 combined 4 igc_ethtool_set_channels(): igc_reinit_queues() -> Default schedule is gone, per Tx ring start and end time are zero - tc qdisc replace dev enp3s0 handle 100 parent root mqprio \ num_tc 4 map 3 3 2 2 0 1 1 1 3 3 3 3 3 3 3 3 \ queues 1@0 1@1 1@2 1@3 hw 1 igc_tsn_offload_apply(): igc_tsn_enable_offload(): -> Writes zeros to IGC_STQT(i) and IGC_ENDQT(i), causing Tx to stall/fail Therefore, restore the default Qbv schedule after changing the number of channels. Furthermore, add a restriction to not allow queue reconfiguration when TSN/Qbv is enabled, because it may lead to inconsistent states. Fixes: c814a2d2d48f ("igc: Use default cycle 'start' and 'end' values for queues") Signed-off-by: Kurt Kanzenbach Reviewed-by: Aleksandr Loktionov Tested-by: Avigail Dahan Acked-by: Vinicius Costa Gomes Signed-off-by: Tony Nguyen --- drivers/net/ethernet/intel/igc/igc_ethtool.c | 4 ++-- drivers/net/ethernet/intel/igc/igc_main.c | 5 +++++ 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/intel/igc/igc_ethtool.c b/drivers/net/ethernet/intel/igc/igc_ethtool.c index e94c1922b97a..3172cdbca9cc 100644 --- a/drivers/net/ethernet/intel/igc/igc_ethtool.c +++ b/drivers/net/ethernet/intel/igc/igc_ethtool.c @@ -1565,8 +1565,8 @@ static int igc_ethtool_set_channels(struct net_device *netdev, if (ch->other_count != NON_Q_VECTORS) return -EINVAL; - /* Do not allow channel reconfiguration when mqprio is enabled */ - if (adapter->strict_priority_enable) + /* Do not allow channel reconfiguration when any TSN qdisc is enabled */ + if (adapter->flags & IGC_FLAG_TSN_ANY_ENABLED) return -EINVAL; /* Verify the number of channels doesn't exceed hw limits */ diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c index 7aafa60ba0c8..89a321a344d2 100644 --- a/drivers/net/ethernet/intel/igc/igc_main.c +++ b/drivers/net/ethernet/intel/igc/igc_main.c @@ -7759,6 +7759,11 @@ int igc_reinit_queues(struct igc_adapter *adapter) if (netif_running(netdev)) err = igc_open(netdev); + if (!err) { + /* Restore default IEEE 802.1Qbv schedule after queue reinit */ + igc_tsn_clear_schedule(adapter); + } + return err; } -- 2.47.1