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kinnirasna

Member

Registered: 2024-12-27

Posts: 4

[SOLVED] Thinkpad monitor backlight issue after sleep

Thinkpad laptop when woken up from sleep randomly decides to increase its brightness and turn the backlight completely off. Restarting fixes the issue. The issue does not happen on windows booted on the same laptop. There is no hint of errors on dmesg output:

grep -i backlight dmesg.txt
[    1.213881] thinkpad_acpi: This ThinkPad has standard ACPI backlight brightness control, supported by the ACPI video driver
[    1.373667] thinkpad_acpi: Standard ACPI backlight interface available, not loading native one

Same output was visible before the issue happend.
dmesg.txt was created after the backlight went off. The brightness file is /sys/class/backlight/amdgpu_bl1/brightness . Increasing brightness after backlight is off does nothing.

I am using 21JTS01700 ThinkPad E16 Gen AMD Ryzen 5 7530U 6 Cores  Radeon Graphics AMD ATI 04:00.0 Barcelo
Desktop: plasma wayland

Last edited by kinnirasna (2024-12-27 10:27:13)

kinnirasna

Member

Registered: 2024-12-27

Posts: 4

Re: [SOLVED] Thinkpad monitor backlight issue after sleep

adding `acpi_backlight=vendor` to grub config fixes the issue but now I am not able to change brightness value with the keys. The brightness file has changed to

/sys/class/backlight/thinkpad_screen/brightness

but writing to it gives input error. Also, the brightness might be on highest value.

Last edited by kinnirasna (2024-12-27 10:06:16)

kinnirasna

Member

Registered: 2024-12-27

Posts: 4

Re: [SOLVED] Thinkpad monitor backlight issue after sleep

**Fixed**:
Added acpi_backlight=native, which uses amdgpu for brightness fixed the issue. I am also able to use the brightness keys now.

kinnirasna

Member

Registered: 2024-12-27

Posts: 4

Re: [SOLVED] Thinkpad monitor backlight issue after sleep

Does anybody know the cause of the issue??