Public bug reported:
'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@: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:c090-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@: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:c080-c080
*-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,
t
