[SOLVED] Realtek rtl8821cu driver needed

Issues & Assistance Networking Support
1

I tried this paru rtl8821cu-morrownr-dkms-git and it did not seem to work for me. I also booted into the LTS kernel. It is not recognizing the adapter. Just trying to breathe some life into this older machine.

System:
  Kernel: 5.15.35-1-lts arch: x86_64 bits: 64 compiler: gcc v: 11.2.0
    parameters: BOOT_IMAGE=/@/boot/vmlinuz-linux-lts
    root=UUID=a1d76239-0e31-48a4-9e47-fc56082cad50 rw rootflags=subvol=@
    quiet quiet splash rd.udev.log_priority=3 vt.global_cursor_default=0
    resume=UUID=b550c8b3-eaae-4413-89e6-6033a8953424 loglevel=3
  Desktop: GNOME v: 42.0 tk: GTK v: 3.24.33 info: cairo-dock
    wm: gnome-shell dm: GDM v: 42.0 Distro: Garuda Linux base: Arch Linux
Machine:
  Type: Desktop System: Dell product: Inspiron 530 v: N/A
    serial: <superuser required> Chassis: type: 3 serial: <superuser required>
  Mobo: Dell model: 0FM586 serial: <superuser required> BIOS: Dell
    v: 1.0.18 date: 02/24/2009
CPU:
  Info: model: Intel Core2 Quad Q6600 bits: 64 type: MCP arch: Core Merom
    family: 6 model-id: 0xF (15) stepping: 0xB (11) microcode: 0xBA
  Topology: cpus: 1x cores: 4 smt: <unsupported> cache: L1: 256 KiB
    desc: d-4x32 KiB; i-4x32 KiB L2: 8 MiB desc: 2x4 MiB
  Speed (MHz): avg: 1761 high: 1824 min/max: 1600/2400 scaling:
    driver: acpi-cpufreq governor: schedutil cores: 1: 1764 2: 1645 3: 1812
    4: 1824 bogomips: 19153
  Flags: ht lm nx pae sse sse2 sse3 ssse3 vmx
  Vulnerabilities:
  Type: itlb_multihit status: KVM: VMX disabled
  Type: l1tf mitigation: PTE Inversion; VMX: EPT disabled
  Type: mds
    status: Vulnerable: Clear CPU buffers attempted, no microcode; SMT disabled
  Type: meltdown mitigation: PTI
  Type: spec_store_bypass status: Vulnerable
  Type: spectre_v1
    mitigation: usercopy/swapgs barriers and __user pointer sanitization
  Type: spectre_v2 mitigation: Retpolines, STIBP: disabled, RSB filling
  Type: srbds status: Not affected
  Type: tsx_async_abort status: Not affected
Graphics:
  Device-1: NVIDIA GT200 [GeForce GTX 260] vendor: eVga.com. driver: nouveau
    v: kernel pcie: gen: 1 speed: 2.5 GT/s lanes: 16 ports: active: DVI-I-2
    empty: DVI-I-1 bus-ID: 01:00.0 chip-ID: 10de:05e2 class-ID: 0300
  Display: x11 server: X.Org v: 21.1.3 with: Xwayland v: 22.1.1
    compositor: gnome-shell driver: X: loaded: nouveau unloaded: modesetting
    alternate: fbdev,nv,vesa gpu: nouveau display-ID: :1 screens: 1
  Screen-1: 0 s-res: 1920x1080 s-dpi: 96 s-size: 508x285mm (20.00x11.22")
    s-diag: 582mm (22.93")
  Monitor-1: DVI-I-2 model: LG (GoldStar) TV serial: <filter> built: 2010
    res: 1920x1080 dpi: 305 gamma: 1.2 size: 160x90mm (6.3x3.54")
    diag: 184mm (7.2") ratio: 16:9 modes: max: 1920x1080 min: 720x400
  Message: Unable to show GL data. Required tool glxinfo missing.
Audio:
  Device-1: Intel 82801I HD Audio vendor: Dell Inspiron 530
    driver: snd_hda_intel v: kernel bus-ID: 00:1b.0 chip-ID: 8086:293e
    class-ID: 0403
  Sound Server-1: ALSA v: k5.15.35-1-lts running: yes
  Sound Server-2: PulseAudio v: 15.0 running: no
  Sound Server-3: PipeWire v: 0.3.50 running: yes
Network:
  Device-1: Intel 82562V-2 10/100 Network vendor: Dell Inspiron 530
    driver: e1000e v: kernel port: ff00 bus-ID: 00:19.0 chip-ID: 8086:10c0
    class-ID: 0200
  IF: enp0s25 state: down mac: <filter>
  Device-2: Realtek 802.11ac NIC type: USB driver: N/A bus-ID: 1-6:6
    chip-ID: 0bda:c811 class-ID: 0000 serial: <filter>
  Device-3: D-Link System DWA-140 RangeBooster N Adapter(rev.B2) [Ralink
  RT3072]
    type: USB driver: rt2800usb bus-ID: 2-4:3 chip-ID: 07d1:3c0a class-ID: 0000
    serial: <filter>
  IF: wlp0s29f7u4 state: up mac: <filter>
Drives:
  Local Storage: total: 2.27 TiB used: 9.68 GiB (0.4%)
  SMART Message: Required tool smartctl not installed. Check --recommends
  ID-1: /dev/sda maj-min: 8:0 vendor: Western Digital
    model: WD1001FALS-40U9B0 size: 931.51 GiB block-size: physical: 512 B
    logical: 512 B speed: 3.0 Gb/s type: N/A serial: <filter> rev: 4F20
    scheme: MBR
  ID-2: /dev/sdb maj-min: 8:16 vendor: Western Digital
    model: WD1001FALS-00J7B1 size: 931.51 GiB block-size: physical: 512 B
    logical: 512 B speed: 3.0 Gb/s type: N/A serial: <filter> rev: 0K05
    scheme: MBR
  ID-3: /dev/sdc maj-min: 8:32 vendor: PNY model: CS900 500GB SSD
    size: 465.76 GiB block-size: physical: 512 B logical: 512 B speed: 3.0 Gb/s
    type: SSD serial: <filter> rev: 0615 scheme: MBR
Partition:
  ID-1: / raw-size: 457.34 GiB size: 457.34 GiB (100.00%)
    used: 9.68 GiB (2.1%) fs: btrfs dev: /dev/sdc1 maj-min: 8:33
  ID-2: /home raw-size: 457.34 GiB size: 457.34 GiB (100.00%)
    used: 9.68 GiB (2.1%) fs: btrfs dev: /dev/sdc1 maj-min: 8:33
  ID-3: /var/log raw-size: 457.34 GiB size: 457.34 GiB (100.00%)
    used: 9.68 GiB (2.1%) fs: btrfs dev: /dev/sdc1 maj-min: 8:33
  ID-4: /var/tmp raw-size: 457.34 GiB size: 457.34 GiB (100.00%)
    used: 9.68 GiB (2.1%) fs: btrfs dev: /dev/sdc1 maj-min: 8:33
Swap:
  Kernel: swappiness: 133 (default 60) cache-pressure: 100 (default)
  ID-1: swap-1 type: zram size: 3.83 GiB used: 22 MiB (0.6%) priority: 100
    dev: /dev/zram0
  ID-2: swap-2 type: partition size: 8.42 GiB used: 0 KiB (0.0%)
    priority: -2 dev: /dev/sdc2 maj-min: 8:34
Sensors:
  System Temperatures: cpu: 40.0 C mobo: N/A
  Fan Speeds (RPM): N/A
Info:
  Processes: 212 Uptime: 31m wakeups: 0 Memory: 3.83 GiB
  used: 2.53 GiB (66.1%) Init: systemd v: 250 tool: systemctl Compilers:
  gcc: 11.2.0 Packages: pacman: 1204 lib: 348 Shell: fish v: 3.4.1
  default: Bash v: 5.1.16 running-in: gnome-terminal inxi: 3.3.15
Garuda (2.6.1-3):
  System install date:     2022-04-23
  Last full system update: 2022-04-24
  Is partially upgraded:   No
  Relevant software:       NetworkManager
  Windows dual boot:       <superuser required>
  Snapshots:               Snapper
  Failed units:
2

Which part did not work?

1 Like
3

If you installed the lts kernel after installing that driver, I think you could try installing the driver again, because I remember reading that it builds better with the lts kernel.

4

After installing adapter not recognized.

5

I did try that.

6

I am not sure what to try now.

7

Try this:

mkdir -p ~/build
cd ~/build
git clone https://github.com/brektrou/rtl8821CU.git
sudo pacman -S bc dkms
cd ~/build/rtl8821CU
sudo ./dkms-install.sh

If you want to uninstall the driver, run:

sudo ./dkms-remove.sh

If your device isn't recognized by the kernel, then:

Install usb_modeswitch :

sudo pacman -S usb_modeswitch

Then run:

sudo usb_modeswitch -KW -v 0bda -p c811

This should change your mode, and your wifi should be recognized.

See:

This should work with kernel 5.17, so you shouldn't need to run the LTS kernel.

4 Likes
8

Should I do this in with the LTS kernel?

9

It hopefully shouldn't matter.

1 Like
10 
mkdir -p ~/build
cd ~/build
git clone https://github.com/brektrou/rtl8821CU.git
sudo pacman -S bc dkms
cd ~/build/rtl8821CU
sudo ./dkms-install.sh

Do this one by one or at once? Getting drivers to work is a new part of linux for me. Until now all my drivers were in the kernel.

11

Try them individually, but it really shouldn't matter.

It will take a while to build the driver. Do not interrupt the process.

1 Like
12

Does it matter if the adapter is plugged in or not?

13

Try both ways if one doesn't work.

1 Like
14

Well, thanks for the help. It sees the dongle. I am still learning. I been trying different things all day. Kudos!! :+1:

15

So is your wifi now working?

1 Like
16

Yes it is. I am connected on it now. How well do those directions translate to other Arch based distros?

17

It should be good on all Arch spins.

Glad it's working for you now.

2 Likes
18

I been searching and trying all kinds of things since yesterday. Some real similar commands. Nothing worked. I had been on manjaro but was ready to try Garuda. Just done with the spyware called Windows.

19

Which kernel are you using?

20

It worked with the ZEN kernel.

1 Like