The MQPRIO (and ETF) offload utilizes the TSN Tx mode. This mode is always
coupled to 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
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 CPU(s).
- 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) -> Boom
Therefore, restore the default Qbv schedule after changing the amount of
channels.
Signed-off-by: Kurt Kanzenbach <[email protected]>
---
drivers/net/ethernet/intel/igc/igc_main.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c
b/drivers/net/ethernet/intel/igc/igc_main.c
index
728d7ca5338bf27c3ce50a2a497b238c38cfa338..e4200fcb2682ccd5b57abb0d2b8e4eb30df117df
100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -7761,6 +7761,8 @@ int igc_reinit_queues(struct igc_adapter *adapter)
if (netif_running(netdev))
err = igc_open(netdev);
+ igc_tsn_clear_schedule(adapter);
+
return err;
}
---
base-commit: 6fc33710cd6c55397e606eeb544bdf56ee87aae5
change-id: 20251107-igc_mqprio_channels-2329166e898b
Best regards,
--
Kurt Kanzenbach <[email protected]>
