Fwd: ath12k driver on Debian 12 - High ping latency and MLO support query on 6.11rc7

[Kalle Valo]

Benoit Masson <benoitm at perenite.com> writes:

> Hi Kalle thanks a million for answering and taking the time!
>
> On Mon, Sep 16, 2024 at 10:28 AM Kalle Valo <kvalo at kernel.org> wrote:
>>
>> > While generally stable, I'm encountering two issues:
>> >
>> > 1. High ping latency/jitter:
>> > - ath12k: 3.5ms to 55ms (40ms jitter)
>>
>> Is this from network to ath12k or from ath12k to network? I recommend
>> testing both.
>
> Below the test both way;
> 1) From station to access point:
> ping 192.168.1.1
> PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.
> 64 bytes from 192.168.1.1: icmp_seq=1 ttl=64 time=13.7 ms
> 64 bytes from 192.168.1.1: icmp_seq=2 ttl=64 time=15.5 ms
> 64 bytes from 192.168.1.1: icmp_seq=3 ttl=64 time=3.70 ms
> 64 bytes from 192.168.1.1: icmp_seq=4 ttl=64 time=12.2 ms
> 64 bytes from 192.168.1.1: icmp_seq=5 ttl=64 time=23.4 ms
> 64 bytes from 192.168.1.1: icmp_seq=6 ttl=64 time=12.8 ms
> 64 bytes from 192.168.1.1: icmp_seq=7 ttl=64 time=13.2 ms
> 64 bytes from 192.168.1.1: icmp_seq=8 ttl=64 time=12.0 ms
> 64 bytes from 192.168.1.1: icmp_seq=9 ttl=64 time=11.9 ms
> 64 bytes from 192.168.1.1: icmp_seq=10 ttl=64 time=23.3 ms
> 64 bytes from 192.168.1.1: icmp_seq=11 ttl=64 time=12.9 ms
> 64 bytes from 192.168.1.1: icmp_seq=12 ttl=64 time=12.2 ms
> 64 bytes from 192.168.1.1: icmp_seq=13 ttl=64 time=6.48 ms
>
> 2) from access point to station:
> ping 192.168.1.169
> PING 192.168.1.169 (192.168.1.169): 56 data bytes
> 64 bytes from 192.168.1.169: seq=0 ttl=64 time=5.582 ms
> 64 bytes from 192.168.1.169: seq=1 ttl=64 time=4.469 ms
> 64 bytes from 192.168.1.169: seq=2 ttl=64 time=357.588 ms
> 64 bytes from 192.168.1.169: seq=3 ttl=64 time=398.582 ms
> 64 bytes from 192.168.1.169: seq=4 ttl=64 time=419.028 ms
> 64 bytes from 192.168.1.169: seq=5 ttl=64 time=449.935 ms
> 64 bytes from 192.168.1.169: seq=6 ttl=64 time=21.677 ms
> 64 bytes from 192.168.1.169: seq=7 ttl=64 time=3.836 ms
> 64 bytes from 192.168.1.169: seq=8 ttl=64 time=370.563 ms
> 64 bytes from 192.168.1.169: seq=9 ttl=64 time=17.126 ms
> 64 bytes from 192.168.1.169: seq=10 ttl=64 time=3.833 ms
> 64 bytes from 192.168.1.169: seq=11 ttl=64 time=58.386 ms
> 64 bytes from 192.168.1.169: seq=12 ttl=64 time=81.823 ms
> 64 bytes from 192.168.1.169: seq=13 ttl=64 time=107.806 ms
> 64 bytes from 192.168.1.169: seq=14 ttl=64 time=170.339 ms
> 64 bytes from 192.168.1.169: seq=15 ttl=64 time=52.075 ms
> 64 bytes from 192.168.1.169: seq=16 ttl=64 time=7.189 ms

Yeah, this look like delay caused by IEEE 802.11 Power Save Mode. But of
course this is just a guess still, not a full analysis :)

> Thanks a million for having me to look in this direction ! Any thoughs
> on power_saving settings for ath12k and best way to make those value
> kept after boot if any in firmware or config of the driver or module
> parameters ? Indeed that would be great to have TWT activated for
> phone and tablet battery saving but ath12k on desktop to ignore it.

Do you use Network Manager? I don't use it but there seems to be a
wifi.powersave setting:

https://askubuntu.com/questions/1386217/wifi-power-management-keeps-turning-on

>> > 2. MLO support:
>> > - When connected via MLO, performance mirrors 6GHz-only connection
>> > - Doesn't appear to utilize all three bands
>> >
>> > Questions:
>> > 1. Are there any recent patches addressing the latency issue for
>> > kernel 6.11rc7?
>>
>> At least I can't think of any fix right now.
>
> Thanks for lettings me know, any though about the firmware binary are
> there beta firmware somewhere that would make sense to test or is the
> linux-firmware git main branch the more recent one ?

If you are feeling brave, the latest firmware images are here:

https://git.codelinaro.org/clo/ath-firmware/ath12k-firmware

And the latest driver is here:

https://git.kernel.org/pub/scm/linux/kernel/git/ath/ath.git/

You can update the firmware and driver independently, there should not
be any dependencies.

>> > 2. Is MLO fully supported by Linux/Qualcomm for this hardware? I'm
>> > willing to test any proposed solutions or gather additional data if
>> > needed.
>>
>> MLO is not yet supported. Once there is something to test we will
>> announce it in this ath12k list.
>
> Perfect I'll be reading the mailing list, if you need tester able to
> compile a kernel and module don't hesitate. or need tester with wifi7
> access point (I only own TP-Link BE800 but is it in beta firmware mode
> with terminal access so I can also do some test the device)

Great, thanks. We will be sending an announcement once there's something
to test, but we are not there yet (even though we just created
ath12k-mlo branch).

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