'no wifi adapter found' in 5.3.0-26-generic with appropriate drivers present otherwise

[Arin Wongprommoon]

'No Wi-Fi Adapter Found' reported in Settings > WiFi.

rfkill lists only Bluetooth:

$ rfkill list all
0: hci0: Bluetooth
 Soft blocked: no
 Hard blocked: no

lspci identifies a wireless device:

$ lspci
00:00.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15d0
00:00.2 IOMMU: Advanced Micro Devices, Inc. [AMD] Device 15d1
00:01.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) PCIe Dummy Host Bridge
00:01.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 15d3
00:01.2 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 15d3
00:01.3 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 15d3
00:08.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Family 17h (Models 00h-0fh) PCIe Dummy Host Bridge
00:08.1 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 15db
00:08.2 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 15dc
00:14.0 SMBus: Advanced Micro Devices, Inc. [AMD] FCH SMBus Controller (rev 61)
00:14.3 ISA bridge: Advanced Micro Devices, Inc. [AMD] FCH LPC Bridge (rev 51)
00:18.0 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15e8
00:18.1 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15e9
00:18.2 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15ea
00:18.3 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15eb
00:18.4 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15ec
00:18.5 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15ed
00:18.6 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15ee
00:18.7 Host bridge: Advanced Micro Devices, Inc. [AMD] Device 15ef
02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 15)
03:00.0 Network controller: Realtek Semiconductor Co., Ltd. RTL8821CE 802.11ac PCIe Wireless Network Adapter
04:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Picasso (rev c1)
04:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Device 15de
04:00.2 Encryption controller: Advanced Micro Devices, Inc. [AMD] Device 15df
04:00.3 USB controller: Advanced Micro Devices, Inc. [AMD] Device 15e0
04:00.4 USB controller: Advanced Micro Devices, Inc. [AMD] Device 15e1
04:00.5 Multimedia controller: Advanced Micro Devices, Inc. [AMD] Device 15e2
04:00.6 Audio device: Advanced Micro Devices, Inc. [AMD] Device 15e3
04:00.7 Non-VGA unclassified device: Advanced Micro Devices, Inc. [AMD] Device 15e6
05:00.0 SATA controller: Advanced Micro Devices, Inc. [AMD] FCH SATA Controller [AHCI mode] (rev 61)

And lshw reports that the wireless network controller is unclaimed:

$ sudo lshw -C network
[sudo] password for arin:
  *-network
       description: Ethernet interface
       product: RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:02:00.0
       logical name: eno1
       version: 15
       serial: 80:e8:2c:bf:4e:96
       capacity: 1Gbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd 1000bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=r8169 firmware=rtl8168h-2_0.0.2 02/26/15 latency=0 link=no multicast=yes port=MII
       resources: irq:49 ioport:3000(size=256) memory:c0904000-c0904fff memory:c0900000-c0903fff
  *-network UNCLAIMED
       description: Network controller
       product: RTL8821CE 802.11ac PCIe Wireless Network Adapter
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:03:00.0
       version: 00
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress cap_list
       configuration: latency=0
       resources: ioport:2000(size=256) memory:c0800000-c080ffff
  *-network
       description: Ethernet interface
       physical id: 2
       logical name: enp4s0f3u2
       serial: 6a:ba:16:cb:94:36
       capabilities: ethernet physical
       configuration: broadcast=yes driver=rndis_host driverversion=22-Aug-2005 firmware=RNDIS device ip=192.168.42.241 link=yes multicast=yes

I've tried reinstalling bcmwl-kernel-source (sudo apt-get install --reinstall bcmwl-kernel-source) but it didn't work.

This issue appeared after a boot into Windows 10 (my machine is dual-boot) in which the OS identified a 'boot error' and 'fixed' it in a black-box way. I've also disabled SecureBoot and cleared the SecureBoot log via the BIOS, but that didn't solve the problem either.

Finally, when I booted Ubuntu using the 5.0.0-37-generic kernel rather than the 5.3.0-26-generic kernel, the WiFi worked normally. I'm not sure exactly which of the steps above was responsible for the problem, but I'm fairly convinced that the new kernel may have something to do with it.

I should note that when I first installed Ubuntu on this machine on 2019-08-10, the WiFi didn't work out of the box and I ran these commands to get it to work:
        git clone https://github.com/tomaspinho/rtl8821ce
        cd rtl8821ce
        chmod +x dkms-install.sh
        chmod +x dkms-remove.sh
        sudo ./dkms-install.sh

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-5.3.0-26-generic 5.3.0-26.28~18.04.1
ProcVersionSignature: Ubuntu 5.3.0-26.28~18.04.1-generic 5.3.13
Uname: Linux 5.3.0-26-generic x86_64
NonfreeKernelModules: wl
ApportVersion: 2.20.9-0ubuntu7.9
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Sun Jan 19 15:54:26 2020
InstallationDate: Installed on 2019-08-10 (161 days ago)
InstallationMedia: Ubuntu 18.04.3 LTS "Bionic Beaver" - Release amd64 (20190805)
SourcePackage: linux-signed-hwe
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[rjurado (rjurado01)]

This work for me: https://askubuntu.com/questions/1149117/tp-link-ac600-archer-t2u-nano-driver-for-ubuntu-18-04/1191835#1191835

[Arin Wongprommoon (arinwongprommoon)]

I've tried that (i.e. ran the four commands described) and it didn't seem to work. Did you do anything else? Thanks anyway!

[Arin Wongprommoon (arinwongprommoon)]

I've gotten it to work now. Seems like I'm missing the driver for RTL8821e. Following the instructions on https://github.com/tomaspinho/rtl8821ce#pcie-activate-state-power-management worked. The key was the PCIe Activate State Power Management bit that I didn't follow through back in January.

Seems common: https://askubuntu.com/questions/1071299/how-to-install-wi-fi-driver-for-realtek-rtl8821ce-on-ubuntu-18-04