Ubuntu kernel update caused WiFi problems

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Latest Ubuntu 24.04.4 LTS kernel and modules update
linux-*-6.8.0-124-generic >> linux-*-6.8.0-134-generic
caused WiFi connection problems.

Namely:

  • Signal strength moves from max to zero and back.
  • WiFi disconnects and reconnects.
  • Connection is slow to crawling to absent.

Proof:

  • Wired connection works fine.
  • Mobile phone on the same WiFi network works.
  • WiFi works with no problems when laptop boots using previous kernel, i.e. linux-*-6.8.0-124-generic

Some more context:

Regulatory domain is set OK.

$ inxi -nx
...
  Device-2: Qualcomm Atheros QCA9565 / AR9565 Wireless Network Adapter
    vendor: AzureWave driver: ath9k v: kernel bus-ID: 03:00.0
  IF: wlp3s0 state: up mac: ...

  $ lspci -nnk | grep -iA3 net
...
03:00.0 Network controller [0280]: Qualcomm Atheros QCA9565 / AR9565 Wireless Network Adapter [168c:0036] (rev 01)
	Subsystem: AzureWave QCA9565 / AR9565 Wireless Network Adapter [1a3b:2130]
	Kernel driver in use: ath9k
	Kernel modules: ath9k

$ journalctl -k -b | grep ath9k
Jul 06 22:21:32 evm kernel: ath9k 0000:03:00.0 wlp3s0: renamed from wlan0

Internet search outlines possible steps, such as

  • Set kernel boot parameters pcie_aspm=off or intel_iommu=off
  • Disable hardware encryption and bluetooth coexistence in /etc/modprobe.d/ath9k.conf like options ath9k nohwcrypt=1 blink=1 btcoex_enable=1

Which of these listed (and not listed yet) options are worth trying, please?

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2

Thanks for the post. I immediately checked my UM 24.04 devices, all running kernel 6.8.0-134-generic :
My Mediacenter:

$ inxi -nx
...
  Device-2: Qualcomm Atheros AR9462 Wireless Network Adapter vendor: Lite-On
    driver: ath9k v: kernel bus-ID: 04:00.0
  IF: wlp4s0 state: up mac: ...

No WiFi problem.

I do have to mention that i have intel_iommu=igfx_off in my bootoptions to prevent the display from flickering although I can not tell if that has any influence on WiFi.

My other wireless equipped device with the same kernel:

$ inxi -nx
...
  Device-1: Intel Jasper Lake PCH CNVi WiFi driver: iwlwifi v: kernel
    bus-ID: 00:14.3
  IF: wlp0s20f3 state: up mac: ..

No special bootoptions and also no Wifi problems at all.

I have to mention though, that none of my devices have bluetooth enabled since I don’t use bluetooth at all.

In your case I would start with “intel_iommu=igfx_off”. The only thing you lose is GPU passthrough for virtual machines.
If that is not enough, try “intel_iommu=off”

Alternatively, you can avoid the mentioned kernel completely by switching to a HWE kernel instead:

linux-image-generic-hwe-24.04 ( 6.17.0-35.35 )
linux-image-generic-hwe-24.04-edge ( 7.0.0-14.14 )

Or keep the older kernel until the next kernel update

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