Altering the backlight dim timeout on a Thinkpad laptop

Question

It seems something else than gnome-power-manager manages the backlight dim timeout on Thinkpads, maybe thinkpad-acpi.

How do you alter the timeout from 5 seconds? (which is very annoying)

Answer 1

I had this issue on a Thinkpad x220. The following message showed up in /var/log/dmesg:

[ 10.262915] thinkpad_acpi: Standard ACPI backlight interface available, not loading native one

You can tell linux to let a vendor specific driver (thinkpad_acpi) handle the backlight by passing the acpi_backlight=vendor option to the kernel.

To do this:

1. Edit /etc/default/grub
2. Add acpi_backlight=vendor to the list of options in GRUB_CMDLINE_LINUX_DEFAULT
3. Run sudo update-grub

The backlight is now managed by thinkpad_acpi and does not dim after 5 secs.