5.18 Zen and rtl8821CU dkms install

So I see a new ZEN 5.18 incoming and installed it and rebooted fine, just is causing an issue with my wifi dongle. Upon reboot it tried but failed to activate the dongle. So I restored from a snapshot and back and running. My question is more of if I install the kernel and the same happens again. Would I need to remove the driver and redo the process? Or what other route to get it to launch the driver again?

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
  Kernel: 5.17.9-zen1-1-zen arch: x86_64 bits: 64 compiler: gcc v: 12.1.0
    parameters: BOOT_IMAGE=/@/boot/vmlinuz-linux-zen
    root=UUID=b4e3b216-a092-473e-8800-311bb9cd5561 rw [email protected]
    quiet quiet splash rd.udev.log_priority=3 vt.global_cursor_default=0
    resume=UUID=0a35d60e-8805-41fb-8ce2-ebab30994957 loglevel=3
  Desktop: GNOME v: 42.1 tk: GTK v: 3.24.34 info: cairo-dock
    wm: gnome-shell dm: GDM v: 42.0 Distro: Garuda Linux base: Arch Linux
  Type: Desktop Mobo: ASUSTeK model: P6X58D PREMIUM v: Rev 1.xx
    serial: <superuser required> BIOS: American Megatrends v: 1501
    date: 05/10/2011
  Info: model: Intel Core i7 950 bits: 64 type: MT MCP arch: Nehalem
    family: 6 model-id: 0x1A (26) stepping: 5 microcode: 0x1D
  Topology: cpus: 1x cores: 4 tpc: 2 threads: 8 smt: enabled cache:
    L1: 256 KiB desc: d-4x32 KiB; i-4x32 KiB L2: 1024 KiB desc: 4x256 KiB
    L3: 8 MiB desc: 1x8 MiB
  Speed (MHz): avg: 1786 high: 2312 min/max: 1600/3068 boost: enabled
    scaling: driver: acpi-cpufreq governor: performance cores: 1: 1632 2: 1679
    3: 1986 4: 1646 5: 1633 6: 1758 7: 1649 8: 2312 bogomips: 49178
  Flags: ht lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx
  Type: itlb_multihit status: KVM: VMX disabled
  Type: l1tf
    mitigation: PTE Inversion; VMX: conditional cache flushes, SMT vulnerable
  Type: mds status: Vulnerable: Clear CPU buffers attempted, no microcode;
    SMT vulnerable
  Type: meltdown mitigation: PTI
  Type: spec_store_bypass
    mitigation: Speculative Store Bypass disabled via prctl
  Type: spectre_v1
    mitigation: usercopy/swapgs barriers and __user pointer sanitization
  Type: spectre_v2 mitigation: Retpolines, IBPB: conditional, IBRS_FW,
    STIBP: conditional, RSB filling
  Type: srbds status: Not affected
  Type: tsx_async_abort status: Not affected
  Device-1: AMD Cypress XT [Radeon HD 5870] driver: radeon v: kernel
    alternate: amdgpu pcie: gen: 2 speed: 5 GT/s lanes: 16 ports:
    active: HDMI-A-1 empty: DP-1,DVI-I-1,DVI-I-2 bus-ID: 03:00.0
    chip-ID: 1002:6898 class-ID: 0300
  Display: x11 server: X.Org v: 21.1.3 with: Xwayland v: 22.1.2
    compositor: gnome-shell driver: X: loaded: radeon unloaded: modesetting
    alternate: fbdev,vesa gpu: radeon 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: HDMI-A-1 mapped: HDMI-0 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.
  Device-1: Intel 82801JI HD Audio vendor: ASUSTeK driver: snd_hda_intel
    v: kernel bus-ID: 00:1b.0 chip-ID: 8086:3a3e class-ID: 0403
  Device-2: AMD Cypress HDMI Audio [Radeon HD 5830/5850/5870 / 6850/6870
    driver: snd_hda_intel v: kernel pcie: gen: 2 speed: 5 GT/s lanes: 16
    bus-ID: 03:00.1 chip-ID: 1002:aa50 class-ID: 0403
  Sound Server-1: ALSA v: k5.17.9-zen1-1-zen running: yes
  Sound Server-2: PulseAudio v: 15.0 running: no
  Sound Server-3: PipeWire v: 0.3.51 running: yes
  Device-1: Realtek 802.11ac NIC type: USB driver: rtl8821cu bus-ID: 1-4:2
    chip-ID: 0bda:c811 class-ID: 0000 serial: <filter>
  IF: wlp0s26f7u4 state: up mac: <filter>
  Local Storage: total: 2.27 TiB used: 1.71 TiB (75.1%)
  SMART Message: Unable to run smartctl. Root privileges required.
  ID-1: /dev/sda maj-min: 8:0 vendor: Seagate model: ST2000DM008-2FR102
    size: 1.82 TiB block-size: physical: 4096 B logical: 512 B speed: 3.0 Gb/s
    type: HDD rpm: 7200 serial: <filter> rev: 0001 scheme: MBR
  ID-2: /dev/sdb maj-min: 8:16 vendor: PNY model: CS900 500GB SSD
    size: 465.76 GiB block-size: physical: 512 B logical: 512 B speed: 6.0 Gb/s
    type: SSD serial: <filter> rev: 0615 scheme: MBR
  ID-1: / raw-size: 457.34 GiB size: 457.34 GiB (100.00%)
    used: 117.08 GiB (25.6%) fs: btrfs dev: /dev/sdb1 maj-min: 8:17
  ID-2: /home raw-size: 457.34 GiB size: 457.34 GiB (100.00%)
    used: 117.08 GiB (25.6%) fs: btrfs dev: /dev/sdb1 maj-min: 8:17
  ID-3: /var/log raw-size: 457.34 GiB size: 457.34 GiB (100.00%)
    used: 117.08 GiB (25.6%) fs: btrfs dev: /dev/sdb1 maj-min: 8:17
  ID-4: /var/tmp raw-size: 457.34 GiB size: 457.34 GiB (100.00%)
    used: 117.08 GiB (25.6%) fs: btrfs dev: /dev/sdb1 maj-min: 8:17
  Kernel: swappiness: 133 (default 60) cache-pressure: 100 (default)
  ID-1: swap-1 type: zram size: 5.78 GiB used: 760.8 MiB (12.9%)
    priority: 100 dev: /dev/zram0
  ID-2: swap-2 type: partition size: 8.42 GiB used: 0 KiB (0.0%)
    priority: -2 dev: /dev/sdb2 maj-min: 8:18
  System Temperatures: cpu: 40.0 C mobo: 39.0 C gpu: radeon temp: 45.0 C
  Fan Speeds (RPM): cpu: 1278 psu: 0 case-1: 767 case-2: 1068 case-3: 0
  Power: 12v: 12.14 5v: N/A 3.3v: 3.20 vbat: N/A
  Processes: 290 Uptime: 27m wakeups: 0 Memory: 5.78 GiB
  used: 2.95 GiB (51.1%) Init: systemd v: 251 tool: systemctl Compilers:
  gcc: 12.1.0 Packages: pacman: 1596 lib: 377 flatpak: 0 Shell: fish v: 3.4.1
  default: Bash v: 5.1.16 running-in: gnome-terminal inxi: 3.3.16
Garuda (2.6.3-2):
  System install date:     2022-04-24
  Last full system update: 2022-05-27
  Is partially upgraded:   Yes
  Relevant software:       NetworkManager
  Windows dual boot:       <superuser required>
  Snapshots:               Snapper
  Failed units: 

I see there are 2 dkms versions in the AUR.
I think this one is more up-to-date, althoghu it has a comment on a minor problem on the latest kernel:

1 Like

I have the 1st one installed now. So they both have an issue with the new kernel. I am thinking I will just wait a few days and see how things change. It works fine with 5.17.9 kernel. I was just excited to see 5.18 with the some of the new changes. You all have anywhere you have changelogs? Aside from the git I would assume.

The first thing to do is rebuild the driver if there is a breakage with a kernel update, however this often does not help.

I have found it sometimes takes up to a month for Realtek Wifi drivers to become compatible with some kernel updates. In the mean time you could try using the LTS kernel until the wifi driver becomes compatible with the newer kernels.

This is just to be expected when using Realtek Wifi adapters. They break on kernel updates with regularity. If your computer is older, and can run the LTS kernel in the interim then it's no big deal. If you can't run the LTS kernel then I would recommend buying another adapter with in kernel driver support.


If I had done my damn research and knew that wifi adapters used proprietary drives I would have picked another one. Everything I have thrown at linux the drivers were just there. Never would have thought a wifi dongle would be the one thing that is an issue. I may have to do that and run the LTS or stay on a kernel that works with the drivers. So just redo the steps and not remove the driver? I did see on one reboot it was trying to start and just could not so it was still there. So that would lead me to believe no need to remove them. So just redo the steps I showed above that I am sure you gave me.

So looks I'm not the only one. I really should have done my research and bought an adapter with open source drivers.

Yes, the morrownr driver you linked to works much better with new kernels. It even works for me on kernel 6.02.
However, I have better luck with it on the vanilla kernels, not the Zen kernels.

Please try to refrain from necrobumping old threads, but thanks for your contribution.