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#1 2021-07-21 12:53:35

Rogrir
Member
Registered: 2021-07-21
Posts: 1

Backlight not working [\_SB.PCI0.PB2], AE_NOT_FOUND

Problem is I can't change backlight and it is always set to 100% (from visibility standpoint).

I tried absolutely every post I could find about backlight like for example https://askubuntu.com/questions/1217133 … egion-y540 with every other solution and many more. I haven't seen any post with the exact problem I have.

Xrandr works properly but it just changes gamma not the real values. When editing "/sys/class/backlight/acpi_video0/brightness" or "/sys/class/backlight/amdgpu_bl0/brightness" values change properly with no visible effect.
I also have passed "acpi_backlight=video nvidia.NVreg_RegistryDwords=EnableBrightnessControl=1" to kernel.
Without the "acpi_backlight=video" acpi doesn't load properly on boot. Systemctl errors that acpi_video0 wasn't found.

On boot I get message:

ACPI Error: AE_NOT_FOUND, During name lookup/catalog (20210331/psobject-220)
ACPI BIOS Error (bug): Could not resolve symbol [\_SB.PCI0.PB2], AE_NOT_FOUND (20210331/dswload2-162)

and this is also the same message that exists in journalctl.

It might be possible that this can only be fixed by BIOS update but I need confirmation.

Relevant neofetch information:

OS: Arch Linux x86_64
Host: 82JU Legion 5 15ACH6H
Kernel: 5.13.4-arch1-1
WM: dwm
Terminal: st
CPU: AMD Ryzen 7 5800H with Radeon Graphics (16) @ 3.200GHz
GPU: NVIDIA GeForce RTX 3060 Mobile / Max-Q
GPU: AMD ATI 06:00.0 Cezanne
Memory: 3154MiB / 15368MiB

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