When I boot into Ubuntu (21.04), my laptop wifi usually stops working after a few minutes. It disconnects from the router, and can no longer detect any nearby routers. There is a workaround: my laptop is set up to dual-boot Windows, and if I boot to Windows and then immediately reboot back to Ubuntu, the wifi always works fine.

My problem seems similar to this one, but the fix that worked for that case (disabling "fast boot" on Windows) does not work in mine.

[Edit]: After further experimentation, it seems that the problem is triggered only when my laptop has been switched off for several hours and then started again. If my wifi is working and then I restart Ubuntu or even power off and immediately power on again, then the wifi seems to continue to work fine. But if I turn the computer off overnight and then power on in the morning, the wifi problem returns. When this happens, the only way to make it work again is by booting Windows and then restarting and booting Ubuntu.

My wifi chip is a Realtek RTL8821CE 802.11ac PCIe. I've pasted the output of a few wifi diagnostic commands below, in case that might help:

This is the output while the wifi is working:

sudo lshw -C network



  *-network

       description: Wireless interface

       product: RTL8821CE 802.11ac PCIe Wireless Network Adapter

       vendor: Realtek Semiconductor Co., Ltd.

       physical id: 0

       bus info: pci@0000:02:00.0

       logical name: wlp2s0

       version: 00

       serial: 28:39:26:70:6a:d9

       width: 64 bits

       clock: 33MHz

       capabilities: pm msi pciexpress bus_master cap_list ethernet physical wireless

       configuration: broadcast=yes driver=rtw_8821ce driverversion=5.11.0-17-generic firmware=N/A ip=192.168.1.7 latency=0 link=yes multicast=yes wireless=IEEE 802.11

       resources: irq:144 ioport:3000(size=256) memory:a4200000-a420ffff





rfkill list



0: ideapad_wlan: Wireless LAN

    Soft blocked: no

    Hard blocked: no

1: ideapad_bluetooth: Bluetooth

    Soft blocked: yes

    Hard blocked: no

2: phy0: Wireless LAN

    Soft blocked: no

    Hard blocked: no

3: hci0: Bluetooth

    Soft blocked: yes

    Hard blocked: no





lspci -nn | grep -i network



02:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8821CE 802.11ac PCIe Wireless Network Adapter [10ec:c821]



uname -r # kernel version

5.11.0-18-generic





iwconfig



wlp2s0    IEEE 802.11  ESSID:"SRISUWAN"  

          Mode:Managed  Frequency:2.457 GHz  Access Point: FC:3F:7C:29:E6:F8   

          Bit Rate=65 Mb/s   Tx-Power=20 dBm   

          Retry short limit:7   RTS thr:off   Fragment thr:off

          Power Management:on

          Link Quality=70/70  Signal level=-28 dBm  

          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0

          Tx excessive retries:0  Invalid misc:12   Missed beacon:0

And this is the output while it's not working:

sudo lshw -C network



*-generic                 

       description: Wireless interface

       product: RTL8821CE 802.11ac PCIe Wireless Network Adapter

       vendor: Realtek Semiconductor Co., Ltd.

       physical id: 0

       bus info: pci@0000:02:00.0

       logical name: wlp2s0

       version: ff

       serial: 28:39:26:70:6a:d9

       width: 32 bits

       clock: 66MHz

       capabilities: bus_master vga_palette cap_list ethernet physical wireless

       configuration: broadcast=yes driver=rtw_8821ce driverversion=5.11.0-17-generic firmware=N/A latency=255 link=no maxlatency=255 mingnt=255 multicast=yes wireless=IEEE 802.11

       resources: irq:144 ioport:3000(size=256) memory:a4200000-a420ffff





rfkill list



0: ideapad_wlan: Wireless LAN

        Soft blocked: no

        Hard blocked: no

1: ideapad_bluetooth: Bluetooth

        Soft blocked: yes

        Hard blocked: no

2: phy0: Wireless LAN

        Soft blocked: no

        Hard blocked: no

3: hci0: Bluetooth

        Soft blocked: yes

        Hard blocked: no





lspci -nn | grep -i network



02:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8821CE 802.11ac PCIe Wireless Network Adapter [10ec:c821] (rev ff)



iwconfig



wlp2s0    IEEE 802.11  ESSID:off/any  

          Mode:Managed  Access Point: Not-Associated   Tx-Power=20 dBm   

          Retry short limit:7   RTS thr:off   Fragment thr:off

          Power Management:on

In response to sancho.s's suggestion, this is the output of inxi -Fxz while the wifi is working:

System:

  Kernel: 5.11.0-18-generic x86_64 bits: 64 compiler: gcc v: 10.2.1 

  Desktop: GNOME 3.38.4 Distro: Ubuntu 21.04 (Hirsute Hippo) 

Machine:

  Type: Laptop System: LENOVO product: 81MU v: Lenovo IdeaPad S145-14IWL 

  serial: <filter> 

  Mobo: LENOVO model: LNVNB161216 v: SDK0Q55756 WIN serial: <filter> 

  UEFI: LENOVO v: ASCN50WW date: 11/24/2020 

Battery:

  ID-1: BAT0 charge: 23.0 Wh condition: 23.0/30.0 Wh (77%) 

  model: LGC L17L2PF1 status: Full 

CPU:

  Info: Quad Core model: Intel Core i5-8265U bits: 64 type: MT MCP 

  arch: Kaby Lake note: check rev: C L2 cache: 6 MiB 

  flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx 

  bogomips: 28800 

  Speed: 800 MHz min/max: 400/1600 MHz Core speeds (MHz): 1: 800 2: 865 

  3: 800 4: 800 5: 799 6: 792 7: 800 8: 794 

Graphics:

  Device-1: Intel WhiskeyLake-U GT2 [UHD Graphics 620] vendor: Lenovo 

  driver: i915 v: kernel bus ID: 00:02.0 

  Device-2: NVIDIA GM108M [GeForce MX110] vendor: Lenovo driver: nvidia 

  v: 460.80 bus ID: 01:00.0 

  Device-3: Acer Integrated Camera type: USB driver: uvcvideo 

  bus ID: 1-7:3 

  Display: x11 server: X.Org 1.20.11 driver: loaded: modesetting,nvidia 

  unloaded: fbdev,nouveau,vesa resolution: 1920x1080~60Hz 

  OpenGL: renderer: GeForce MX110/PCIe/SSE2 v: 4.6.0 NVIDIA 460.80 

  direct render: Yes 

Audio:

  Device-1: Intel Cannon Point-LP High Definition Audio vendor: Lenovo 

  driver: snd_hda_intel v: kernel bus ID: 00:1f.3 

  Sound Server: ALSA v: k5.11.0-18-generic 

Network:

  Device-1: Realtek RTL8821CE 802.11ac PCIe Wireless Network Adapter 

  vendor: Lenovo driver: rtw_8821ce v: N/A port: 3000 bus ID: 02:00.0 

  IF: wlp2s0 state: up mac: <filter> 

Bluetooth:

  Device-1: Realtek Bluetooth Radio type: USB driver: btusb v: 0.8 

  bus ID: 1-10:4 

  Report: ID: hci0 state: down address: <filter> 

Drives:

  Local Storage: total: 476.94 GiB used: 41.07 GiB (8.6%) 

  ID-1: /dev/nvme0n1 vendor: Intel model: SSDPEKNW512G8L size: 476.94 GiB 

  temp: 31.9 C 

Partition:

  ID-1: / size: 23.35 GiB used: 15.24 GiB (65.3%) fs: ext4 

  dev: /dev/nvme0n1p4 

  ID-2: /boot/efi size: 256 MiB used: 33.6 MiB (13.1%) fs: vfat 

  dev: /dev/nvme0n1p1 

  ID-3: /home size: 207.11 GiB used: 25.8 GiB (12.5%) fs: ext4 

  dev: /dev/nvme0n1p6 

Swap:

  ID-1: swap-1 type: partition size: 8.06 GiB used: 0 KiB (0.0%) 

  dev: /dev/nvme0n1p7 

Sensors:

  System Temperatures: cpu: 58.0 C mobo: N/A gpu: nvidia temp: 52 C 

  Fan Speeds (RPM): N/A 

Info:

  Processes: 321 Uptime: 4h 34m Memory: 7.65 GiB used: 3.77 GiB (49.3%) 

  Init: systemd runlevel: 5 Compilers: gcc: 10.3.0 Packages: 2685 

  Shell: Bash v: 5.1.4 inxi: 3.3.01 

And the output of inxi -Fxz while the wifi is not working:

System:

  Kernel: 5.11.0-18-generic x86_64 bits: 64 compiler: gcc v: 10.2.1 

  Desktop: GNOME 3.38.4 Distro: Ubuntu 21.04 (Hirsute Hippo) 

Machine:

  Type: Laptop System: LENOVO product: 81MU v: Lenovo IdeaPad S145-14IWL 

  serial: <filter> 

  Mobo: LENOVO model: LNVNB161216 v: SDK0Q55756 WIN serial: <filter> 

  UEFI: LENOVO v: ASCN50WW date: 11/24/2020 

Battery:

  ID-1: BAT0 charge: 23.0 Wh condition: 23.0/30.0 Wh (77%) 

  model: LGC L17L2PF1 status: Full 

CPU:

  Info: Quad Core model: Intel Core i5-8265U bits: 64 type: MT MCP 

  arch: Kaby Lake note: check rev: C L2 cache: 6 MiB 

  flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx 

  bogomips: 28800 

  Speed: 800 MHz min/max: 400/3900 MHz Core speeds (MHz): 1: 800 2: 800 

  3: 800 4: 795 5: 800 6: 767 7: 800 8: 718 

Graphics:

  Device-1: Intel WhiskeyLake-U GT2 [UHD Graphics 620] vendor: Lenovo 

  driver: i915 v: kernel bus ID: 00:02.0 

  Device-2: NVIDIA GM108M [GeForce MX110] vendor: Lenovo driver: nvidia 

  v: 460.80 bus ID: 01:00.0 

  Device-3: Acer Integrated Camera type: USB driver: uvcvideo bus ID: 1-7:3 

  Display: x11 server: X.Org 1.20.11 driver: loaded: modesetting,nvidia 

  unloaded: fbdev,nouveau,vesa resolution: 1920x1080~60Hz 

  OpenGL: renderer: GeForce MX110/PCIe/SSE2 v: 4.6.0 NVIDIA 460.80 

  direct render: Yes 

Audio:

  Device-1: Intel Cannon Point-LP High Definition Audio vendor: Lenovo 

  driver: snd_hda_intel v: kernel bus ID: 00:1f.3 

  Sound Server: ALSA v: k5.11.0-18-generic 

Network:

  Device-1: Realtek RTL8821CE 802.11ac PCIe Wireless Network Adapter 

  driver: rtw_8821ce v: N/A port: 4000 bus ID: 02:00.0 

  IF: wlp2s0 state: down mac: <filter> 

Bluetooth:

  Device-1: Realtek Bluetooth Radio type: USB driver: btusb v: 0.8 

  bus ID: 1-10:4 

  Report: ID: hci0 state: down address: <filter> 

Drives:

  Local Storage: total: 476.94 GiB used: 40.89 GiB (8.6%) 

  ID-1: /dev/nvme0n1 vendor: Intel model: SSDPEKNW512G8L size: 476.94 GiB 

  temp: 30.9 C 

Partition:

  ID-1: / size: 23.35 GiB used: 15.17 GiB (65.0%) fs: ext4 

  dev: /dev/nvme0n1p4 

  ID-2: /boot/efi size: 256 MiB used: 33.6 MiB (13.1%) fs: vfat 

  dev: /dev/nvme0n1p1 

  ID-3: /home size: 207.11 GiB used: 25.69 GiB (12.4%) fs: ext4 

  dev: /dev/nvme0n1p6 

Swap:

  ID-1: swap-1 type: partition size: 8.06 GiB used: 0 KiB (0.0%) 

  dev: /dev/nvme0n1p7 

Sensors:

  System Temperatures: cpu: 54.0 C mobo: N/A gpu: nvidia temp: 48 C 

  Fan Speeds (RPM): N/A 

Info:

  Processes: 285 Uptime: 11m Memory: 7.65 GiB used: 2.08 GiB (27.2%) 

  Init: systemd runlevel: 5 Compilers: gcc: 10.3.0 Packages: 2685 

  Shell: Bash v: 5.1.4 inxi: 3.3.01 

Further information. As requested, I ran the following series of commands while the wifi was working and while it was not:

$ nmcli networking connectivity

$ nmcli radio all

$ nmcli connection show

$ nmcli device status 

$ nmcli device show wlp2s0

$ dmesg -T | grep rtw

$ nmcli networking on

$ nmcli device connect wlp2s0

$ nmcli connection up SRISUWAN

The results were as follows:

While the wifi was working: paste

While the wifi was not working: paste

While the wifi was not working after an extended power-off: paste