Ubuntu 22.04: RTL8821CE-based wifi not working

I upgraded from 20.04 LTS to 22.04 LTS. PC has RTL8821CE wifi hardware on board. On 20.04 wifi was working OK; on 22.04 no wifi.

Note: the PC when I bought it last year came with 20.04 pre-installed and at that time wifi was not working. On 20.04 I managed to make it work going through many posts. Now with 22.04 I can not succeed.

I went through many posts regarding the trouble with RTL8821CE but have apparently missed the key sequence of commands to correct things. Can someone dive into the infos I took (see attached) to try to understand what I can try to do to make wifi work?

Don't know if and how to attach a file with the infos I collected so I have to included them here below.

I don't "like" point 15 below with output like: [ 7.805121] 8821ce: disagrees about version of symbol __cfg80211_alloc_event_skb [ 7.805128] 8821ce: Unknown symbol __cfg80211_alloc_event_skb (err -22) [ 7.805140] 8821ce: disagrees about version of symbol wiphy_register [ 7.805142] 8821ce: Unknown symbol wiphy_register (err -22)

but I am not able to link these messages to specific actions I can try.

Thanks a lot and sorry for the long post :-) Regards Fred

fred@fred-CoreBookLite:~$ lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 22.04.1 LTS Release: 22.04 Codename: jammy fred@fred-CoreBookLite:~$

fred@fred-CoreBookLite:~$ uname -r 5.15.0-60-generic

Here are the infos I took so far ( I only report RTL8821CE related infos).

1. fred@fred-CoreBookLite:~$ sudo lshw

configuration: boot=normal chassis=notebook family=Default string sku=CBL15C

   *-pci
         description: PCI bridge
         product: Gemini Lake PCI Express Root Port
         vendor: Intel Corporation
         physical id: 14
         bus info: pci@0000:00:14.0
         version: f6
         width: 32 bits
         clock: 33MHz
         capabilities: pci pciexpress msi pm normal_decode bus_master cap_list
         configuration: driver=pcieport
         resources: irq:122 ioport:e000(size=4096) memory:a1100000-a11fffff
       *-network UNCLAIMED
            description: Network controller
            product: RTL8821CE 802.11ac PCIe Wireless Network Adapter
            vendor: Realtek Semiconductor Co., Ltd.

2. fred@fred-CoreBookLite:~$ sudo lshw -short

/0/100/14/0 network RTL8821CE 802.11ac PCIe Wireless Network Adapter

3. fred@fred-CoreBookLite:~$ inxi -Fz Network: Device-1: Realtek RTL8821CE 802.11ac PCIe Wireless Network Adapter driver: N/A (seems to me there is no wifi driver !!!!!!?????)

4. fred@fred-CoreBookLite:~$ lspci -knn | grep -A 2 -i net 01:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8821CE 802.11ac PCIe Wireless Network Adapter [10ec:c821]
   Subsystem: Realtek Semiconductor Co., Ltd. RTL8821CE 802.11ac PCIe Wireless Network Adapter [10ec:c821] Kernel modules: rtw88_8821ce, 8821ce

5. fred@fred-CoreBookLite:~$ lspci -vvnn 01:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8821CE 802.11ac PCIe Wireless Network Adapter [10ec:c821] Subsystem: Realtek Semiconductor Co., Ltd. RTL8821CE 802.11ac PCIe Wireless Network Adapter [10ec:c821] Control: I/O- Mem- BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- SERR- <PERR- INTx- Interrupt: pin A routed to IRQ 255 Region 0: I/O ports at e000 [disabled] [size=256] Region 2: Memory at a1100000 (64-bit, non-prefetchable) [disabled] [size=64K] Capabilities: Kernel modules: rtw88_8821ce, 8821ce

6. fred@fred-CoreBookLite:~$ nmcli general STATE CONNECTIVITY WIFI-HW WIFI WWAN-HW WWAN
   connected full enabled enabled enabled enabled fred@fred-CoreBookLite:~$

7. fred@fred-CoreBookLite:~$ nmcli connection NAME UUID TYPE DEVICE
   Wired connection 2 6caf9b67-1f13-31d3-aa8e-5c767b600758 ethernet enx00e04c534458 AC94-2.4GHz 1268664e-14fb-45d7-b5a4-125dde514150 wifi --
   AC94-guest 49dfbe6e-52bb-4f6e-ad38-59692e24fcc1 wifi --
   Fred Ulefone Note 9P a748d918-1d11-4273-ae06-40b0ae93b14c wifi --
   H369A904462 67a7b8f9-ed9d-4a3a-a47d-a42c018ccfa5 wifi --
   Wired connection 1 7ff51297-d011-3d6a-ae55-975bafee5f5b ethernet --

Question: If the wifi card does not work on 22.04, how can 22.04 know about the wifi networks I have? Info taken from the old 20.04 installation?

8. fred@fred-CoreBookLite:~$ ifconfig (= ifconfig -a) enx00e04c534458: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 192.168.1.95 netmask 255.255.255.0 broadcast 192.168.1.255 inet6 fe80::e7f4:a64e:41b4:6e76 prefixlen 64 scopeid 0x20 ether 00:e0:4c:53:44:58 txqueuelen 1000 (Ethernet) RX packets 3885 bytes 2900350 (2.9 MB) RX errors 30 dropped 5 overruns 6 frame 39 TX packets 3781 bytes 1335914 (1.3 MB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

enx1609010d2dc2: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 ether 16:09:01:0d:2d:c2 txqueuelen 1000 (Ethernet) RX packets 0 bytes 0 (0.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 0 bytes 0 (0.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10 loop txqueuelen 1000 (Local Loopback) RX packets 13709 bytes 1120093 (1.1 MB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 13709 bytes 1120093 (1.1 MB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

That is: no wifi interface (like wlan0 for example)

9. fred@fred-CoreBookLite:~$ rfkill list all 0: hci0: Bluetooth Soft blocked: no Hard blocked: no

10. fred@fred-CoreBookLite:~$ lshw -C network WARNING: you should run this program as super-user. *-network UNCLAIMED
    description: Network controller product: RTL8821CE 802.11ac PCIe Wireless Network Adapter vendor: Realtek Semiconductor Co., Ltd. physical id: 0 bus info: pci@0000:01:00.0 version: 00 width: 64 bits clock: 33MHz capabilities: cap_list configuration: latency=0 resources: ioport:e000(size=256) memory:a1100000-a110ffff

11. fred@fred-CoreBookLite:~$ dkms status backport-iwlwifi/9858, 5.15.0-58-generic, x86_64: installed backport-iwlwifi/9858, 5.15.0-60-generic, x86_64: installed rtl8821ce/5.5.2.1~ppa, 5.15.0-58-generic, x86_64: installed (WARNING! Diff between built and installed module!) rtl8821ce/5.5.2.1~ppa, 5.15.0-60-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.13.0-35-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.13.0-37-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.13.0-39-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.13.0-40-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.13.0-41-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.13.0-44-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.13.0-48-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.13.0-51-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.13.0-52-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.15.0-41-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.15.0-46-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.15.0-48-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.15.0-50-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.15.0-52-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.15.0-53-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.15.0-56-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.15.0-57-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.15.0-58-generic, x86_64: built rtl8821ce/v5.5.2_34066.20200325, 5.15.0-60-generic, x86_64: installed rtl8821ce/v5.5.2_34066.20200325, 5.6.11-microtech, x86_64: installed fred@fred-CoreBookLite:~$

12. fred@fred-CoreBookLite:~$ sudo apt install --reinstall git dkms build-essential linux-headers-$(uname -r) Estrazione di linux-headers-5.15.0-60-generic (5.15.0-60.66) su (5.15.0-60.66).. . Configurazione di linux-headers-5.15.0-60-generic (5.15.0-60.66)... /etc/kernel/header_postinst.d/dkms:

• dkms: running auto installation service for kernel 5.15.0-60-generic

8821ce.ko: Running module version sanity check. !!!!!Error! Module version v5.5.2_34066.20200325_COEX20180712-3232 for 8821ce.ko is not newer than what is already found in kernel 5.15.0-60-generic (v5.5.2_3406 6.20200325_COEX20180712-3232). You may override by specifying --force.

depmod.... ...done. Configurazione di dkms (2.8.7-2ubuntu2.1)... Configurazione di git (1:2.34.1-1ubuntu1.8)... Configurazione di build-essential (12.9ubuntu3)... Elaborazione dei trigger per man-db (2.10.2-1)... Cloning into 'rtl8821ce'... remote: Enumerating objects: 1777, done. remote: Counting objects: 100% (112/112), done. remote: Compressing objects: 100% (81/81), done. remote: Total 1777 (delta 47), reused 67 (delta 31), pack-reused 1665 Receiving objects: 100% (1777/1777), 5.98 MiB | 654.00 KiB/s, done. Resolving deltas: 100% (976/976), done. About to run dkms install steps... Error! DKMS tree already contains: rtl8821ce-v5.5.2_34066.20200325 You cannot add the same module/version combo more than once. Module rtl8821ce/v5.5.2_34066.20200325 already built for kernel 5.15.0-60-generic (x86_64).

8821ce.ko: Running module version sanity check.

!!!!!Good news! Module version v5.5.2_34066.20200325_COEX20180712-3232 for 8821ce.ko exactly matches what is already found in kernel 5.15.0-60-generic. DKMS will not replace this module. You may override by specifying --force.

depmod... Finished running dkms install steps.

13. fred@fred-CoreBookLite:~$ sudo apt install rtl8821ce-dkms Lettura elenco dei pacchetti... Fatto Generazione albero delle dipendenze... Fatto Lettura informazioni sullo stato... Fatto
    rtl8821ce-dkms è già alla versione più recente (2:5.5.2.1~focal10). 0 aggiornati, 0 installati, 0 da rimuovere e 0 non aggiornati. fred@fred-CoreBookLite:~$

It says that rtl8821ce-dkms already is at the most recent version (2:5.5.2.1~focal10)

14. fred@fred-CoreBookLite:~$ ls -al /lib/modules/$(uname -r)/updates/dkms total 9572 drwxr-xr-x 2 root root 4096 feb 15 12:17 . drwxr-xr-x 3 root root 4096 feb 10 11:08 .. -rw-r--r-- 1 root root 3844525 feb 10 11:08 8821ce.ko

15. fred@fred-CoreBookLite:~$ sudo dmesg | grep 8821 [ 7.805121] 8821ce: disagrees about version of symbol __cfg80211_alloc_event_skb [ 7.805128] 8821ce: Unknown symbol __cfg80211_alloc_event_skb (err -22) [ 7.805140] 8821ce: disagrees about version of symbol wiphy_register [ 7.805142] 8821ce: Unknown symbol wiphy_register (err -22) [ 7.805154] 8821ce: disagrees about version of symbol cfg80211_remain_on_channel_expired [ 7.805155] 8821ce: Unknown symbol cfg80211_remain_on_channel_expired (err -22) [ 7.805188] 8821ce: disagrees about version of symbol cfg80211_vendor_cmd_reply [ 7.805189] 8821ce: Unknown symbol cfg80211_vendor_cmd_reply (err -22) [ 7.805206] 8821ce: disagrees about version of symbol cfg80211_del_sta_sinfo [ 7.805207] 8821ce: Unknown symbol cfg80211_del_sta_sinfo (err -22) [ 7.805220] 8821ce: disagrees about version of symbol wiphy_unregister [ 7.805221] 8821ce: Unknown symbol wiphy_unregister (err -22) [ 7.805265] 8821ce: disagrees about version of symbol cfg80211_ch_switch_notify [ 7.805266] 8821ce: Unknown symbol cfg80211_ch_switch_notify (err -22) [ 7.805279] 8821ce: disagrees about version of symbol ieee80211_get_channel_khz [ 7.805280] 8821ce: Unknown symbol ieee80211_get_channel_khz (err -22) [ 7.805298] 8821ce: disagrees about version of symbol cfg80211_ready_on_channel [ 7.805299] 8821ce: Unknown symbol cfg80211_ready_on_channel (err -22) [ 7.805343] 8821ce: disagrees about version of symbol wiphy_free [ 7.805344] 8821ce: Unknown symbol wiphy_free (err -22) [ 7.805350] 8821ce: disagrees about version of symbol wiphy_new_nm [ 7.805351] 8821ce: Unknown symbol wiphy_new_nm (err -22) [ 7.805358] 8821ce: disagrees about version of symbol cfg80211_get_bss [ 7.805359] 8821ce: Unknown symbol cfg80211_get_bss (err -22) [ 7.805385] 8821ce: disagrees about version of symbol __cfg80211_send_event_skb [ 7.805387] 8821ce: Unknown symbol __cfg80211_send_event_skb (err -22) [ 7.805409] 8821ce: disagrees about version of symbol cfg80211_disconnected [ 7.805410] 8821ce: Unknown symbol cfg80211_disconnected (err -22) [ 7.805419] 8821ce: disagrees about version of symbol cfg80211_michael_mic_failure [ 7.805420] 8821ce: Unknown symbol cfg80211_michael_mic_failure (err -22) [ 7.805430] 8821ce: disagrees about version of symbol cfg80211_ibss_joined [ 7.805431] 8821ce: Unknown symbol cfg80211_ibss_joined (err -22) [ 7.805483] 8821ce: disagrees about version of symbol cfg80211_scan_done [ 7.805484] 8821ce: Unknown symbol cfg80211_scan_done (err -22) [ 7.805498] 8821ce: disagrees about version of symbol cfg80211_roamed [ 7.805499] 8821ce: Unknown symbol cfg80211_roamed (err -22) [ 7.805503] 8821ce: disagrees about version of symbol cfg80211_put_bss [ 7.805504] 8821ce: Unknown symbol cfg80211_put_bss (err -22) [ 7.805521] 8821ce: disagrees about version of symbol cfg80211_connect_done [ 7.805522] 8821ce: Unknown symbol cfg80211_connect_done (err -22) [ 7.805543] 8821ce: disagrees about version of symbol cfg80211_unlink_bss [ 7.805545] 8821ce: Unknown symbol cfg80211_unlink_bss (err -22) [ 7.805560] 8821ce: disagrees about version of symbol cfg80211_inform_bss_frame_data [ 7.805561] 8821ce: Unknown symbol cfg80211_inform_bss_frame_data (err -22) [ 7.805572] 8821ce: disagrees about version of symbol cfg80211_new_sta [ 7.805573] 8821ce: Unknown symbol cfg80211_new_sta (err -22) [ 7.805589] 8821ce: disagrees about version of symbol __cfg80211_alloc_reply_skb [ 7.805590] 8821ce: Unknown symbol __cfg80211_alloc_reply_skb (err -22) [ 7.805601] 8821ce: disagrees about version of symbol wiphy_apply_custom_regulatory [ 7.805602] 8821ce: Unknown symbol wiphy_apply_custom_regulatory (err -22) [ 7.805609] 8821ce: disagrees about version of symbol cfg80211_mgmt_tx_status [ 7.805610] 8821ce: Unknown symbol cfg80211_mgmt_tx_status (err -22) [ 7.805615] 8821ce: disagrees about version of symbol cfg80211_rx_mgmt_khz [ 7.805616] 8821ce: Unknown symbol cfg80211_rx_mgmt_khz (err -22) [ 7.812602] Bluetooth: hci0: RTL: examining hci_ver=08 hci_rev=000c lmp_ver=08 lmp_subver=8821 [ 7.813588] Bluetooth: hci0: RTL: loading rtl_bt/rtl8821c_fw.bin [ 7.815764] Bluetooth: hci0: RTL: loading rtl_bt/rtl8821c_config.bin fred@fred-CoreBookLite:~$

We notice this in your sudo dkms status:

backport-iwlwifi/9858, 5.15.0-60-generic, x86_64: installed

I believe that backport-iwlwifi-dkms installs its own custom version of cfg80211 among possibly others. It conflicts with the version usually found in the kernel and which your installed driver 8821ce is built to use.

Since you have no Intel wireless device, which uses iwlwifi, I suggest that you remove the conflicting driver suite:

sudo apt purge backport-iwlwifi-dkms

Reboot. Your wireless should now be working.