This is my first time tracking down a kernel bug, so it's taking me a little while as I learn the bisection & kernel compilation procedure.
As an initial step, I have isolated the problem to something Ubuntu-specific. I have now tried running several mainline 5.4 kernels including, e.g., 5.4.17-050417-generic and found, to my surprise, the wireless signal is strong on those mainline kernels. To summarize my testing: BAD: 20.04 runs a signed Ubuntu 5.4 or 5.6 kernel GOOD: 18.04.4 (live usb) runs the default signed 5.3 kernel 20.04 runs unsigned mainline 5.3, 5.4, 5.8 kernels As a step towards a bisection, I've tried to boot a signed Ubuntu 5.3 kernel (taken from 18.04) on 20.04, but this hangs at the "Loading initial ramdisk" stage -- presumably due to some incompatibility between 18.04 and 20.04. I'll next attempt to compile the Ubuntu 5.3 kernel myself, which will hopefully boot on 20.04. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1885663 Title: RTL8822BE [10ec:b822] Subsystem [103c:831b] wifi regression Status in linux package in Ubuntu: Incomplete Bug description: This wireless adapter worked well under 18.04.4 (kernel 5.3) but has poor range after installing 20.04 (kernel 5.4). This is testing a 2.4GHz connection. While the received signal strength appears to be the same with either kernel, the transmitted signal is much weaker under the 5.4 kernel (as assessed from the wifi access point running OpenWrt): the 5.4 kernel yields ~10-20 lower dBm than the 5.3 kernel. This greatly reduces the usable wifi range. To summarize testing: 5.3.0-28-generic (Booting off a 18.04.4 live USB) shows good signal. 5.4.0-39-generic (latest supported on 20.04) is problematic 5.6.0-1011-oem (installed from standard repos) is problematic mainline kernel 5.8.0-050800-generic shows good signal. Ideas to further narrow down this regression? ProblemType: Bug DistroRelease: Ubuntu 20.04 Package: linux-image-5.4.0-39-generic 5.4.0-39.43 ProcVersionSignature: Ubuntu 5.4.0-39.43-generic 5.4.41 Uname: Linux 5.4.0-39-generic x86_64 ApportVersion: 2.20.11-0ubuntu27.3 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: johnson 745 F.... pulseaudio CasperMD5CheckResult: skip CurrentDesktop: ubuntu:GNOME Date: Mon Jun 29 23:18:24 2020 InstallationDate: Installed on 2020-05-29 (32 days ago) InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423) Lsusb: Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 001 Device 003: ID 05c8:022a Cheng Uei Precision Industry Co., Ltd (Foxlink) HP Webcam Bus 001 Device 002: ID 0bda:b00b Realtek Semiconductor Corp. Bluetooth Radio Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub MachineType: HP HP Stream Laptop 11-ah0XX ProcEnviron: SHELL=/bin/bash LANG=en_US.UTF-8 TERM=xterm-256color XDG_RUNTIME_DIR=<set> PATH=(custom, no user) ProcFB: 0 i915drmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-39-generic root=UUID=d161feb8-d49a-4c0c-b954-e14175cdae0b ro quiet splash vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-5.4.0-39-generic N/A linux-backports-modules-5.4.0-39-generic N/A linux-firmware 1.187 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 05/23/2018 dmi.bios.vendor: Insyde dmi.bios.version: F.02 dmi.board.asset.tag: Type2 - Board Asset Tag dmi.board.name: 84FC dmi.board.vendor: HP dmi.board.version: 06.17 dmi.chassis.asset.tag: Chassis Asset Tag dmi.chassis.type: 10 dmi.chassis.vendor: HP dmi.chassis.version: Chassis Version dmi.modalias: dmi:bvnInsyde:bvrF.02:bd05/23/2018:svnHP:pnHPStreamLaptop11-ah0XX:pvr:rvnHP:rn84FC:rvr06.17:cvnHP:ct10:cvrChassisVersion: dmi.product.family: 103C_5335KV HP Stream dmi.product.name: HP Stream Laptop 11-ah0XX dmi.product.sku: 4ND15UA#ABA dmi.sys.vendor: HP To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1885663/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp