//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 ^^

  • RAM@discuss.tchncs.deOP
    3·
    3 months ago

    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 ?

    • Successful_Try543
      2·
      3 months ago

      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.

      • RAM@discuss.tchncs.deOP
        2·
        3 months ago

        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 :)