Wifi dongle halts the system

[champignoom]

Fresh Manjaro downloaded yesterday installed on a desktop without builtin wifi adapter. Two wifi dongles at hand.

Dongle 1: inxi gives me “Realtek 802.11ac NIC” with chip-ID=0bda:c811, but the wifi setting page remains “No Wi-Fi Adapter Found”. But this dongle works on Ubuntu out of the box, without rtl8821cu or any such random drivers.

Dongle 2: it works for like 30s, during which I could connect to a network and open Firefox, but suddenly the system halts and responds to absolutely nothing. Caplock/numlock indicator on the keyboard doesn’t respond. The magic REISUB no longer works either. Again, the dongle works on Ubuntu without problem.

Any help on either dongle is appreciated.

Developers might be interested in the second one, cuz it seems to me an indicator of a serious bug deep down, in which case I’d like to help the debugging.

Manjaro: 22.0, kernel=6.1.1-1
Ubuntu for comparison: 21.10, kernel=5.13.0-52

[Mirdarthos]

Hi @champignoom, and welcome!

@champignoom

Dongle 1: inxi gives me “Realtek 802.11ac NIC” with chip-ID=0bda:c811, but the wifi setting page remains “No Wi-Fi Adapter Found”. But this dongle works on Ubuntu out of the box, without rtl8821cu or any such random drivers.

I find it surprising that this one works at all. Accoring to this page:

We have not found a driver for the device in any Linux kernel versions up to 6.1 according to the LKDDb.

But also according to that page:

You need to install one of the following additional drivers for the device to work properly:

• brektrou/rtl8821CU
• smp79/rtl8821CU
• whitebatman2/rtl8821CU

And that driver seems to be in the AUR:

$ pamac searchrtl8821CU
[...]
rtl8821cu-dkms-git                                                                                                                                                                                                                5.4.1118f1bc7e8-1     AUR
rtl8821cu chipset driver

(I recommend installing the `dkms1 one, as that will be rebuilt on kernel updates, where the other ones wouldn’t.

So you can install it with:

pamac buid rtl8821cu-dkms-git

And reboot. If everything worked according to plan, your wireless should now work.

If, however, it doesn’t reply to this thread and provide the info according to:

[HowTo] Provide System Information

Welcome to Manjaro! To allow all of us helpful people on this forum TO HELP YOU, we need some basic information about your system. This probably means you described the symptoms of your problem, but now we need some more information to know where the origin of your issue is exactly. Someone else probably linked you to this tutorial, so if you’re reading this in response to a question, please click the link above this text to bring you to the full and unabridged text of the tutorial…

also, then provide the output of:

lsmod

Hope this helps!

Edit:

Regarding:

@champignoom

Dongle 2: it works for like 30s, during which I could connect to a network and open Firefox, but suddenly the system halts and responds to absolutely nothing. Caplock/numlock indicator on the keyboard doesn’t respond. The magic REISUB no longer works either. Again, the dongle works on Ubuntu without problem.

All I can say is

---

Tip:

When posting terminal output, copy the output and paste it here, wrapped in three (3) backticks, before AND after the pasted text. Like this:

```
pasted text
```

This will just cause it to be rendered like this:

Sed
sollicitudin dolor
eget nisl elit id
condimentum
arcu erat varius
cursus sem quis eros.

Instead of like this:

Sed sollicitudin dolor eget nisl elit id condimentum arcu erat varius cursus sem quis eros.

Alternatively, paste the text you wish to format as terminal output, select all pasted text, and click the </> button on the taskbar. This will indent the whole pasted section with one TAB, causing it to render the same way as described above.

Thereby increasing legibility thus making it easier for those trying to provide assistance.

For more information, please see:

@Fabby

On this forum here you need to have Trust Level 1 (=TL1) to be able to post screenshots and links in-line.

That’s dumb! Why is that?

Well, that’s because on our old forum we got tons of screenshots of text, links to SPAM, PR0N and other things you don’t want on a forum, so all the new users are prohibited from posting links and pics because of a few bad actors.

---

Also, if your language isn’t English, please prepend any and all terminal commands with LC_ALL=C. For example:

LC_ALL=C bluetoothctl

This will just cause the terminal output to be in English, making it easier to understand and debug.

[champignoom]

Thanks for the help, but it seems that brektrou/rtl8821CU is incompatible with the latest kernel.

Is there any way to see in Ubuntu which driver is in use for the dongle? I think it should not be this rtl8821CU, as lsmod shows nothing matching *8821*.

[Mirdarthos]

Look for something *rtl or *rlt. It might not be it. But if it is…