28.05.2021 01:47, Dmitry Osipenko пишет:

27.05.2021 19:42, Arend van Spriel пишет:

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On 5/26/2021 5:10 PM, Dmitry Osipenko wrote:

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Hello,

After updating to Ubuntu 21.04 I found two problems related to the
BRCMF_C_GET_ASSOCLIST using an older BCM4329 SDIO WiFi.

1. The kernel is spammed with:

  ieee80211 phy0: brcmf_cfg80211_dump_station: BRCMF_C_GET_ASSOCLIST
unsupported, err=-52
  ieee80211 phy0: brcmf_cfg80211_dump_station: BRCMF_C_GET_ASSOCLIST
unsupported, err=-52
  ieee80211 phy0: brcmf_cfg80211_dump_station: BRCMF_C_GET_ASSOCLIST
unsupported, err=-52

Which happens apparently due to a newer NetworkManager version that
pokes dump_station() periodically. I sent [1] that fixes this noise.

[1]
https://patchwork.kernel.org/project/linux-wireless/list/?series=480715

Right. I noticed this one and did not have anything to add to the
review/suggestion.

Please feel free to add yours r-b to the patches if they are good to you.

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2. The other much worse problem is that WiFi eventually dies now with
these errors:

...
  ieee80211 phy0: brcmf_cfg80211_dump_station: BRCMF_C_GET_ASSOCLIST
unsupported, err=-52
  brcmfmac: brcmf_sdio_bus_rxctl: resumed on timeout
  ieee80211 phy0: brcmf_cfg80211_dump_station: BRCMF_C_GET_ASSOCLIST
unsupported, err=-110
  ieee80211 phy0: brcmf_proto_bcdc_query_dcmd: brcmf_proto_bcdc_msg
failed w/status -110

 From this point all firmware calls start to fail with err=-110 and
WiFi doesn't work anymore. This problem is reproducible with 5.13-rc
and current -next, I haven't checked older kernel versions. Somehow
it's worse using a recent -next, WiFi dies quicker.

What's interesting is that I see that there is always a pending signal
in brcmf_sdio_dcmd_resp_wait() when timeout happens. It looks like the
timeout happens when there is access to a swap partition, which stalls
system for a second or two, but this is not 100%. Increasing
DCMD_RESP_TIMEOUT doesn't help.

The timeout error (-110) can have two root causes that I am aware off.
Either the firmware died or the SDIO layer has gone haywire. Not sure if
that swap partition is on eMMC device, but if so it could be related.
You could try generating device coredump. If that also gives -110 errors
we know it is the SDIO layer.

Coredump is a good idea, thank you. The swap partition is on external SD
card, everything else is on eMMC.

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Please let me know if you have any ideas of how to fix this trouble
properly or if you need need any more info.

Removing BRCMF_C_GET_ASSOCLIST firmware call entirely from the driver
fixes the problem.

My guess is that reducing interaction with firmware is what is avoiding
the issue and not so much this specific firmware command. As always it
is good to know the conditions in which the issue occurs. What is the
hardware platform you are running Ubuntu on? Stuff like that.

That's an older Acer A500 NVIDIA Tegra20 tablet device [1]. I may also
try to reproduce problem on Tegra30 Nexus 7 with BCM4330.

[1]
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/tegra20-acer-a500-picasso.dts

Thank you very much for the suggestions. I will try to collect more info
and come back with the report.

I was testing this for the past weeks and the problem is not
reproducible anymore. Apparently something got fixed in linux-next. I
haven't tried to bisect the fix since it's a bit too painful to do.

Still there are occasional -110 errors when system stalls on a memory
swap, but WiFi keeps working now.