Brightness on Thinkpad L480

laufdi · Jul 17, 2020

On pressing Fn-F5 or Fn_F6 I get a delayed brightness change and kernel messages:

Code:

Jul 17 13:54:33 tp kernel: acpi_ec0: EcCommand: no response to 0x84
Jul 17 13:54:33 tp syslogd: last message repeated 1 times
Jul 17 13:54:33 tp kernel: acpi_ec0: GPE query failed: AE_NO_HARDWARE_RESPONSE

setting debug.acpi.ec.timeout to some higher value as suggested does not help, only delays everything even more.

Mjölnir · Jul 17, 2020

The kernel module acpi_ibm(4) is very outdated, it works for older ThinkPads but for the newer Lenovo TPs it does not work well. You can instead use graphics/intel-backlight. If you have plenty of time, you may tinker to get a solution to use acpi_ibm(4) together with a devd(8) script.

Brightness on Thinkpad L480

laufdi

Mjölnir