I tried activating the thinklight on a thinkpad x200 (libreboot 2016 + trisquel 9) using the usual shortcut Fn+Pgup. It doesn't work.
From what I can gather, the thinkpad_acpi drivers should load during startup. This is not the case /sys/devices/platform/thinkpad_acpi/leds/tpacpi::thinklight doesn't exist.
Otherwise brightness and other Fn-related shortcuts are functional.
Is this standard libreboot behavior ? (I read somewhere that the thinklight is bios-activated).
PS: There is a useless reddit thread about this: https://www.reddit.com/r/thinkpad/comments/6z0aon/x200libreboot_help_controlling_thinklight_by/
The Thinklight is controlled by the EC, which is NOT controlled by Coreboot/Libreboot, it may have a bug try this:
*Reinstall the original propietary BIOS from your backup(you have made a backup, did you?)
*Update the BIOS to the latest version
*Check if your EC version in your BIOS is =>1.06
*Install latest libreboot and retry
If all this fails, check your xev and logs at the moment of pressing the button, and check if the light works at all(hardware failure?)