Ubuntu 20.04.3 LTS Wifi Issues [resolved]

[mynameisfiber]

On a clean install of Ubuntu 20.04.3 LTS, I was getting frequent disconnects and high latency. These were being triggered by a microcode error, seen in the syslog as:

[21639.740121] iwlwifi 0000:01:00.0: Microcode SW error detected. Restarting 0x0.

In order to fix this, I turned off powersave on the card (which I don't think actually fixed the issue, but from previous experience it will generally help with wifi performance) and I disabled 11n and bt_coex parameters for the iwlwifi module.

# cat /etc/NetworkManager/conf.d/default-wifi-powersave-on.conf 
[connection]
wifi.powersave = 2
# 2 == off. 3 == on.

# cat /etc/modprobe.d/iwlwifi-options.conf 
options iwlwifi 11n_disable=1
options iwlwifi bt_coex_active=0

This seems to have fixed the issue. For reference, the corresponding firmware microcodes on the system are from linux-firmware==1.187.20 and I have the following relevant versions:

$ ls /lib/firmware/ | grep iwlwifi-cc-a0
iwlwifi-cc-a0-46.ucode
iwlwifi-cc-a0-48.ucode
iwlwifi-cc-a0-55.ucode
iwlwifi-cc-a0-59.ucode
iwlwifi-cc-a0-63.ucode

It does seem though that version 59 is loaded instead of 63

$ sudo grep cc-a0 /var/log/syslog 
[   12.211690] iwlwifi 0000:01:00.0: loaded firmware version 59.601f3a66.0 cc-a0-59.ucode op_mode iwlmvm

This is the exact card I have,

charm ~:$ sudo lshw -C network
  *-network                 
       description: Wireless interface
       product: Wi-Fi 6 AX200
       vendor: Intel Corporation
       physical id: 0
       bus info: pci@0000:01:00.0
       logical name: wlp1s0
       version: 1a
       serial: 08:5b:d6:83:ec:49
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical wireless
       configuration: broadcast=yes driver=iwlwifi driverversion=5.11.0-41-generic firmware=59.601f3a66.0 cc-a0-59.ucode ip=192.168.0.181 latency=0 link=yes multicast=yes wireless=IEEE 802.11
       resources: irq:84 memory:d0700000-d0703fff