can't adjust my screen_brightness

[Bella]

Im using my machine since 20.12.20 and use it in dual boot with windows10 alongside.

Hotkeys and adjusting brightness via GUI both broken, since formatting the machine on day 1.

Before formatting, adjusting brightness was possible in windows10, but not in ubuntu or other linux distro, that I tried out.

There is no bar in the top right corner under the bar for adjusting the sound output.

Because "The description is too long. If you have lots of text to add, attach a file to the bug instead." the description is added as .txt-file.

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: linux-image-5.4.0-58-generic 5.4.0-58.64
ProcVersionSignature: Ubuntu 5.4.0-58.64-generic 5.4.73
Uname: Linux 5.4.0-58-generic x86_64
ApportVersion: 2.20.11-0ubuntu27.14
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: bella 2076 F.... pulseaudio
 /dev/snd/pcmC0D0p: bella 2076 F...m pulseaudio
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Tue Jan 5 13:58:37 2021
InstallationDate: Installed on 2020-12-25 (11 days ago)
InstallationMedia: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
MachineType: LENOVO 20VH001CGE
ProcFB: 0 EFI VGA
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-5.4.0-58-generic root=UUID=2850ca84-1b0f-4cdd-ac66-5b9c964159e6 ro quiet splash acpi_backlight=vendor vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-5.4.0-58-generic N/A
 linux-backports-modules-5.4.0-58-generic N/A
 linux-firmware 1.187.6
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/08/2020
dmi.bios.vendor: LENOVO
dmi.bios.version: R1FET29W (1.03 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20VH001CGE
dmi.board.vendor: LENOVO
dmi.board.version: SDK0J40697 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias: dmi:bvnLENOVO:bvrR1FET29W(1.03):bd10/08/2020:svnLENOVO:pn20VH001CGE:pvrThinkPadL13Gen2:rvnLENOVO:rn20VH001CGE:rvrSDK0J40697WIN:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad L13 Gen 2
dmi.product.name: 20VH001CGE
dmi.product.sku: LENOVO_MT_20VH_BU_Think_FM_ThinkPad L13 Gen 2
dmi.product.version: ThinkPad L13 Gen 2
dmi.sys.vendor: LENOVO

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

This change was made by a bot.

[Alex Hung (alexhung)]

Did you try removing "acpi_backlight=vendor" from kernel parameters?

[Bella (63ll4)]

wow. that finally solved my issue.
thank you very much alex hung!

how do I make this change permanent and also working on my windows os?

[Bella (63ll4)]

UPDATE: made the change permanent and also fixed the issue for windows

[Alex Hung (alexhung)]

Good to know that fixed your problem!