ath12k: WCN7850 beacon loss on narrower BSS after prior 160 MHz 6GHz association

[Jacob Wilson]

Hi,

I have found what appears to be a repeatable issue with the QCNCM865
M.2 (WCN7850 hw2.0) Wi-Fi radio on the 6.19 kernel. I searched through
https://lore.kernel.org/ath12k/ and didn't find a report matching what
I found here, but apologies if I missed something.

After having a prior association to a 160MHz 6GHz BSS, when
disconnecting and associating to a BSS with a narrower channel width
(80, 40, or 20MHz), repeated CTRL-EVENT-BEACON-LOSS messages are seen
in wpa_supplicant logs, and the connection to the BSS with the
narrower channel width becomes unstable.

This "beacon loss" state persists until either a system reboot or a
manual reload of the PCIe device via:
  echo 1 | sudo tee /sys/bus/pci/devices/0000:01:00.0/remove
  echo 1 | sudo tee /sys/bus/pci/rescan

My setup is as follows:
OS: Gentoo Linux x86_64
Host: HP EliteBook 845 14 inch G10 Notebook
Kernel: 6.19.10, Gentoo dist-kernel (sys-kernel/gentoo-kernel)
/proc/sys/kernel/tainted = 0
Wi-Fi stack: NetworkManager and wpa_supplicant

Test WAPs:
Edgecore EAP105 (160MHz on 6GHz)
Ruckus R310 (80MHz on 5GHz)
Extreme AP3000 (40MHz on 6GHz)

To reproduce:
1. I connect to the 160 Mhz 6GHz AP. The connection at that point is stable.
2. Disconnect manually from the 160 MHz AP and connect to any of my
APs running a narrower channel width
3. Monitor wpa_supplicant logs, and I will see CTRL-EVENT-BEACON-LOSS
within a few seconds, on a repeating cycle.

Of note - when my connection is initially to a narrower channel width
AP (80, 40, 20MHz), and I move from, say, 80MHz to 40MHz, the
connection remains stable and beacon loss events are not seen.

I'd be happy to provide full dmesg, .config, iw reg get output, or test
patches if it's helpful

Thanks,
Jacob Wilson