brightness slider working but not the brightness in ubuntu 20.04

[sakthee]

brightness control not working

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: linux-image-5.4.0-46-generic 5.4.0-46.50
ProcVersionSignature: Ubuntu 5.4.0-46.50-generic 5.4.60
Uname: Linux 5.4.0-46-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.9
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: sakthee 4780 F.... pulseaudio
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Sun Sep 6 01:01:49 2020
HibernationDevice: RESUME=UUID=5441a3ef-63d8-4455-b227-f27cec9e699f
InstallationDate: Installed on 2020-06-12 (85 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Release amd64 (20180426)
MachineType: Hewlett-Packard HP 241 G1
ProcFB: 0 EFI VGA
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-46-generic root=/dev/sda2 ro quiet nomodeset acpi_osi=linux
RelatedPackageVersions:
 linux-restricted-modules-5.4.0-46-generic N/A
 linux-backports-modules-5.4.0-46-generic N/A
 linux-firmware 1.187.3
RfKill:
 0: phy0: Wireless LAN
  Soft blocked: no
  Hard blocked: no
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/27/2015
dmi.bios.vendor: Insyde
dmi.bios.version: F.31
dmi.board.asset.tag: Base Board Asset Tag
dmi.board.name: 8072
dmi.board.vendor: Hewlett-Packard
dmi.board.version: KBC Version 70.07
dmi.chassis.asset.tag: 5CG5380YZX
dmi.chassis.type: 10
dmi.chassis.vendor: Hewlett-Packard
dmi.chassis.version: Chassis Version
dmi.modalias: dmi:bvnInsyde:bvrF.31:bd04/27/2015:svnHewlett-Packard:pnHP241G1:pvr0988100000400010060370081:rvnHewlett-Packard:rn8072:rvrKBCVersion70.07:cvnHewlett-Packard:ct10:cvrChassisVersion:
dmi.product.family: 103C_5335KV G=N L=CON B=HP S=PRE X=MIN
dmi.product.name: HP 241 G1
dmi.product.sku: P4C96PC#ACJ
dmi.product.version: 0988100000400010060370081
dmi.sys.vendor: Hewlett-Packard

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.

[Alex Hung (alexhung)]

Did you try to remove the kernel parameter "acpi_osi=linux"?

Please run "ls /sys/class/backlight/" to see what backlight interfaces are available.