I'm using a heavily patched 21.02 based OpenWRT build on Gateworks Ventana platform (imx6). I'm at the moment testing Intel AX200 based MPCIE-cards (Alfa Networks AX200U) for station mode. RX traffic seems to be no problem, but within the TX traffic I see appr. 15% of the frames missing (captured on the AP). The AP is a Cisco Catalyst 9300 with an SSID with WPA2-PSK, 80 MHz channel on non DFS-channels.
The weird thing is, that enabling power for the bluetooth-device (via bluetoothctl -> power on) results in less loss (appr. 7%). The results where measured with iperf3 in udp mode. And missing frames have been verified by a packet capture on the AP.
I already tested using the iwlwifi from backports 5.15.8 and firmware version 66. Still the same. Does anybody know some hints, how to get more advanced debug logs, than the known one from the log buffer and the kernel log buffer? Or does somebody maybe have some hints, what I can try to tackle the error down?
I tried to go ahead to see if it as an already known code bug ... So I'm running on OpenWRT trunk with backported iwlwifi driver from iwlwifi-next kernel git (Firmware 71, as 72 is not released by Intel yet).
Still the same. Now I will enable debugfs and try if I see something with the trace scripts.
Any help/hint would be still appreciated.
Now I did some debug tracing on 21.02. I used the following trace command and ran iperf on a second session:
trace-cmd record -e iwlwifi -e iwlwifi_msg -e iwlwifi_io -e tcp -e iwlwifi_ucode -e net -e sock
The output typically looks like this:
iperf3-11001  2634.186937: net_dev_queue: dev=wlan1 skbaddr=0xe6835bb0 len=55
iperf3-11001  2634.186941: net_dev_start_xmit: dev=wlan1 queue_mapping=0 skbaddr=0xe6835bb0 vlan_tagged=0 vlan_proto=0x0000 vlan_tci=0x0000 protocol=0x0800 ip_summed=3 len=55 data_len=1 network_offset=14 transport_offset_valid=1 transport_offset=34 tx_flags=0 gso_size=0 gso_segs=1 gso_type=0x1
iperf3-11001  2634.186954: iwlwifi_dbg: TX to [0|0] Q:3 - seq: 0x2fc len 75
iperf3-11001  2634.186962: iwlwifi_dev_tx: [0000:07:00.0] TX 1c (101 bytes) skbaddr=0xe6835bb0
iperf3-11001  2634.186968: iwlwifi_dbg: Q:3 WR: 0xfd
iperf3-11001  2634.186971: iwlwifi_dev_iowrite32: [0000:07:00.0] write io[0x460] = 0x300fd)
iperf3-11001  2634.186976: iwlwifi_dbg: TXQ of sta 0c:75:bd:b6:96:40 tid 0 is now empty
iperf3-11001  2634.186980: net_dev_xmit: dev=wlan1 skbaddr=0xe6835bb0 len=55 rc=0
The complete trace-report looks good.
Maybe somebody has a hint, where to search next