iwlwifi: Stops receiving unicast

["Rafael Ávila de Espíndola" <rafael@espindo.la>]

My laptop with an Intel 8265 stops receiving unicast packets after a day
or so. My current test setup has 3 machines in the same wifi network

* The laptop with the intel 8265 which has network problems
* A phone
* A desktop running wireshark in monitor mode

If I try to ping the phone from the laptop, the machine in monitor mode
sees frames going from my laptop to phone and back. This is the case
both when my laptop is seeing the pongs and when it isn't.

The wifi network is encrypted, so I can't be sure the frames have the
pings and pongs, but the data length is always 100 bytes.

When the ping program is not getting the pongs, neither wireshark or a
small xdp program on the laptop will see them either, so they are being
dropped at a lower level. Wireshark on the laptop still reports
broadcasts (like ARP) and multicasts (like mDNS).

I have had similar issues with both a 6.1.32-0-lts and 6.3.4-0-edge
alpine kernels, so I suspect a firmware issue, which is:

firmware-version: 36.ca7b901d.0 8265-36.ucode

Following
https://wireless.wiki.kernel.org/en/users/drivers/iwlwifi/debugging I
have enabled CONFIG_IWLWIFI_DEBUG and CONFIG_IWLWIFI_DEVICE_TRACING and
installed trace-cmd, but I don't know what to check next.

I have also reported this at https://bugzilla.kernel.org/show_bug.cgi?id=217535

Thanks,
Rafael