Fresh kubuntu install wifi is ok except 5 and 6 ghz band

[telkel31]

Hi guys,

im a decades old windows user and wanted to try Linux with Kubuntu. I made a dual boot on a separate sata ssd with refind and so far, I must say that almost everything runs smooth.

Except one thing : I don't know why but my wifi 7 pci card which worked fine on windows is causing me troubles. I can only see and connect to 2.4 Ghz networks. I have 5 ghz and 6 ghz with separate ssids but they won't show up and I'm so unable to connect. I tried to search by myself but Im struggling, it may be a pilot problem (ath12k), I have no idea how to solve it, can you help me ?

[oshunluvr]

ATH12K is the driver. Post your hardware info.

[Snowhog]

Are you 5 and 6 Ghz SSID's hidden?

[telkel31]

Thanks for your reply, my wifi card is a Gigabyte GC-Wifi7, I tried some command to see precise hardware reference, here is the output :

lspci -k | grep -A 3 -i network
03:00.0 Network controller: Qualcomm Technologies, Inc WCN785x Wi-Fi 7(802.11be) 320MHz 2x2 [FastConnect 7800] (rev 01)
Subsystem: Foxconn International, Inc. Device e0fb
Kernel driver in use: ath12k_pci
Kernel modules: ath12k

So it seems to be a Qualcomm Fastconnect 7800 (WCN785x) wifi controller inside.

For Snowhog, my SSID's are not hidden, I can see them on my android phone without problems.

[claydoh]

So, some basics: which Kubuntu release and kernel version.

I am suspecting we need a more current firmware, possibly, maybe, but really the current kernel (which are the same in LTS and current release) should be ok here, supposedly.

[telkel31]

Sorry ! real linux newbie here

lsb_release -a
No LSB modules are available.
Distributor ID:Ubuntu
Description:Ubuntu 25.10
Release:25.10
Codename:questing

uname -r
6.17.0-5-generic


Im surprised this command returns "ubuntu" and not "kubuntu" but maybe this is because kubuntu is derived from ubuntu ?

[claydoh]

Im surprised this command returns "ubuntu" and not "kubuntu" but maybe this is because kubuntu is derived from ubuntu ?

Kubuntu *is* Ubuntu, using Plasma instead of Gnome as the UI. The actual OS is 100% identical.

https://ubuntu.com/desktop/flavors
https://wiki.ubuntu.com/UbuntuFlavors

Things like Linux Mint, neon, and others are actually derived distros, as they usually add their own software repos on top of Ubuntu's

You can also use System Settings, and K Info Center to see system info:


Now, as to the wifi, I have no idea what you need.

6.17.0-5-generic

Have you updated your system since the install? Assuming the 2.4 connection is usable? You seem to be a number of kernel patches behind.

[telkel31]

Thank you for the clarification and k info center tip.

My ISP modem/router has multiples antennas and is able to generate wifi networks on 2.4 Ghz, 5 Ghz and 6 Ghz, I gave them separate SSIDs (network1_2.4GHz, network2_5Ghz and network3_6GHz). I used to connect with 6 ghz wifi network on windows which means about 1 Gbit/s speed in download. On Kubuntu the wifi panel only show network1_2.4GHz. It works flawlessly but at a reduced speed (about 120 Mbit/s).

In discovery, update section says I'm up to date but not sure if this is the good way to check kernel updates.

[claydoh]

In discovery, update section says I'm up to date but not sure if this is the good way to check kernel updates.

Discover is where you'd see them.




I doubt my 25.10 here being a VM has any effect on this, but see mine is at -8


To double check, we can look at what apt thinks

Here is mine:

$ sudo apt update

<  snipped stuff :)  >

$ apt policy linux-image-generic
linux-image-generic:
Installed: 6.17.0-8.8
Candidate: 6.17.0-8.8
Version table:
*** 6.17.0-8.8 500
           500 http://us.archive.ubuntu.com/ubuntu questing-updates/main amd64 Packages
           500 http://security.ubuntu.com/ubuntu questing-security/main amd64 Packages
          100 /var/lib/dpkg/status
6.17.0-5.5 500
          500 http://us.archive.ubuntu.com/ubuntu questing/main amd64 Packages​

[telkel31]

Strange, here is my discover "about this system"


and here the return of apt :
apt policy linux-image-generic
linux-image-generic:
Installé : 6.17.0-8.8
Candidat : 6.17.0-8.8
Table de version :
*** 6.17.0-8.8 500
500 http://archive.ubuntu.com/ubuntu questing-updates/main amd64 Packages
500 http://security.ubuntu.com/ubuntu questing-security/main amd64 Packages
100 /var/lib/dpkg/status
6.17.0-5.5 500
500 http://archive.ubuntu.com/ubuntu questing/main amd64 Packages


Discover says 6.17.0-5, apt says 6.17.0-8.8.

[telkel31]

Ok I found the problem with kernel, it was from refind, last kernel was installed but not loaded. I was able to switch to kernel 6.17.0-8 but it still didn't change anything.