this post was submitted on 18 Aug 2024
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[SOLVED] Wifi adapter suddenly stopped working after 1 year (discuss.tchncs.de)
submitted 3 weeks ago* (last edited 3 weeks ago) by [email protected] to c/[email protected]
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//Solution:

I installed this driver (https://github.com/morrownr/8821au-20210708).

The driver however, did not work until I ran a script called remove-driver.sh from the driver that I used to use (https://github.com/morrownr/8821cu-20210916). Then the wifi adapter started working again :)

Thanks a lot for the help - I am still not really sure what the problem actually was, but I'm very thankful for having my internet connection back :)

//Original post below:

Hey :)

I've been using a wifi adapter for my computer for about a year. A few days ago, it suddenly stopped working. It no longer shows up when I run 'nmcli device' in the terminal. When running 'lsusb' it still shows up as 'Realtek Semiconductor Corp. 802.11ac NIC'.

To my knowledge I hadn't updated anything before it stopped working. After it had stopped working, I used usb-tethering from my phone to do a system update, hoping it would fix the problem. I think one of the updates was a linux firmware update. Anyways, it didn't fix anything.

The adapter didn't work out of the box. It arrived with a driver called 'RTL88x2BU' and a document stating that it was compatible with the following chip drivers for linux: RTL8811AU RTL8811CU RTL8812BU RTL8814AU

I couldn't get the driver it arrived with to work, so instead I downloaded this driver and have been using it until it stopped working. https://github.com/morrownr/8821cu-20210916

this driver only states that it supports some linux kernel version. I'm using '6.8.0-40-generic', which it does not claim to suppport. I download this driver, which should support my kernel, but it didn̈́'t work either. https://github.com/morrownr/8821au-20210708

I've tried running lsmod on my system, and it seems to be, that no wifi driver even starts. The only thing I can remember doing just prior to my internet not working, was running 'systemctl disable jellyfin.service'. I doubt that has anything to do with this, but I'm not sure what else it could be. My only other theory is, maybe the usb wifi adapter hardware just gave up.

Any help is appreciated ^^

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[–] [email protected] 1 points 3 weeks ago* (last edited 3 weeks ago) (6 children)

Are the networking service and network manager up and running?
systemctl status networking
systemctl status network-manager
What does rfkill list wifi show?

[–] [email protected] 2 points 3 weeks ago* (last edited 3 weeks ago) (1 children)

'systemctl status networking' gives

Unit networking.service could not be found.

'systemctl status network-manager' gives

Unit network-manager.service could not be found.

'rfkill list wifi' gives nothing

//edit:

'systemctl status NetworkManager' gives

● NetworkManager.service - Network Manager
     Loaded: loaded (/lib/systemd/system/NetworkManager.service; enabled; v>
     Active: active (running) since Mon 2024-08-19 08:12:34 CEST; 1h 54min >
       Docs: man:NetworkManager(8)
   Main PID: 770 (NetworkManager)
      Tasks: 3 (limit: 9251)
     Memory: 11.1M
        CPU: 5.564s
     CGroup: /system.slice/NetworkManager.service
             └─770 /usr/sbin/NetworkManager --no-daemon

I can't find any alternative names for 'networking'.

[–] [email protected] 2 points 3 weeks ago (1 children)

ip link show should list all available interfaces. If the wifi card isn't there, then it's not initialised after all.

[–] [email protected] 3 points 3 weeks ago* (last edited 3 weeks ago) (1 children)

it does not show up from ip link show.

what does it mean, that it is not initialised ?

//EDIT:

I ran a script called remove-driver.sh from the driver that I used to use (https://github.com/morrownr/8821cu-20210916) and now the wifi adapter is up and running again :)

Thanks a lot for the help - I'm not really sure, what was wrong, but I'm very thankful for the help :)

Was the problem, that I had a bad driver installed ?

[–] [email protected] 2 points 3 weeks ago* (last edited 3 weeks ago) (1 children)

Great!

what does it mean, that it is not initialised ?

Initialisation procedure of a new device how I've understood it yet (I'm no expert, if someone knows better, you're welcome to correct or enhance):
Once the device is attached, the system notices that there is device type xxxx:yyyy on usbx-y and loads the respective kernel module/driver which then creates a file (Unix philosophy: everything is a file) somewhere in /dev e.g. wlan0 (usually you can see this in the dmesg output. In your output there was 'nothing', i.e. this didn't happen) which is used for I/O of data and tells the networking service that there is a new interface. Then, the networking service makes the interface usable for internet connection.

Was the problem, that I had a bad driver installed?

Probably some important script was accidentally deleted. As far as I remember, you driver is managed by DKMS which takes care of compiling the module after each kernel update, so maybe some information got lost there.

[–] [email protected] 2 points 3 weeks ago (1 children)

thanks for the answer :)

I just tried to remove and insert the wifi adapter, and now the dmesg has a message about loading a driver :)

[  503.972087] usb 1-1.1: new high-speed USB device number 6 using ehci-pci
[  504.050778] usb 1-1.1: New USB device found, idVendor=0bda, idProduct=1a2b, bcdDevice= 2.00
[  504.050785] usb 1-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[  504.050786] usb 1-1.1: Product: DISK
[  504.050788] usb 1-1.1: Manufacturer: Realtek
[  504.051140] usb-storage 1-1.1:1.0: USB Mass Storage device detected
[  504.051798] scsi host0: usb-storage 1-1.1:1.0
[  504.824569] usb 1-1.1: USB disconnect, device number 6
[  504.996877] usb 1-1.1: new high-speed USB device number 7 using ehci-pci
[  505.075654] usb 1-1.1: New USB device found, idVendor=0bda, idProduct=c811, bcdDevice= 2.00
[  505.075666] usb 1-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[  505.075670] usb 1-1.1: Product: 802.11ac NIC
[  505.075672] usb 1-1.1: Manufacturer: Realtek
[  505.075675] usb 1-1.1: SerialNumber: 123456
[  505.078252] rtw_8821cu 1-1.1:1.0: Firmware version 24.8.0, H2C version 12
[  505.474619] rtw_8821cu 1-1.1:1.0 wlxa0d7683022a3: renamed from wlan0

for some reason, it loads the old driver still. rtw_8821cu instead of rtw_8821au. I'm a tad confused, but I'm happy it's working :)

thanks a lot for the help :)

[–] [email protected] 1 points 3 weeks ago

I don't know what kernel version you use, but from 6.2 the Linux kernel has this driver built-in. So maybe it doesn't use the 'newer' 3rd party 8821au-driver, as the native driver has higher priority. https://linux-hardware.org/?id=usb:0bda-c811

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