I have this issue as well on elementaryOS based on Ubuntu 18.04: Linux Celer 5.4.0-52-generic #57~18.04.1-Ubuntu SMP Thu Oct 15 14:04:49 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
Tried booting with thinkpad-acpi.brightness_enable=1 acpi_backlight=vendor But no luck either. There is something in `/sys/class/backlight` but writing to `brightness` has no effect. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1895782 Title: Screen brightness adjustment doesn't work on Lenovo Thinkpad T14 AMD gen1 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+bug/1895782/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs