С твоим патчем (https://github.com/vaskas/openbsd-acpithinkpad) вот с какими ошибками вылетает (amd4, 5.6-beta):

../../../../dev/acpi/acpithinkpad.c:151: error: redefinition of 'acpithinkpad_models_to_help'
../../../../dev/acpi/acpithinkpad.c:130: error: previous definition of 'acpithinkpad_models_to_help' was here
../../../../dev/acpi/acpithinkpad.c:155: error: redefinition of 'thinkpad_brightness_help'
../../../../dev/acpi/acpithinkpad.c:134: error: previous definition of 'thinkpad_brightness_help' was here
../../../../dev/acpi/acpithinkpad.c:159: error: redefinition of 'min_fan_temps'
../../../../dev/acpi/acpithinkpad.c:138: error: previous definition of 'min_fan_temps' was here
../../../../dev/acpi/acpithinkpad.c:167: error: redefinition of 'thinkpad_staged_fan'
../../../../dev/acpi/acpithinkpad.c:146: error: previous definition of 'thinkpad_staged_fan' was here
../../../../dev/acpi/acpithinkpad.c: In function 'thinkpad_hotkey':
../../../../dev/acpi/acpithinkpad.c:447: error: 'THINKPAD_BUTTON_FN_F6' undeclared (first use in this function)
../../../../dev/acpi/acpithinkpad.c:447: error: (Each undeclared identifier is reported only once
../../../../dev/acpi/acpithinkpad.c:447: error: for each function it appears in.)
../../../../dev/acpi/acpithinkpad.c: At top level:
../../../../dev/acpi/acpithinkpad.c:630: error: redefinition of 'thinkpad_set_fan_level'
../../../../dev/acpi/acpithinkpad.c:623: error: previous definition of 'thinkpad_set_fan_level' was here
*** Error 1 in /usr/src/sys/arch/amd64/compile/GENERIC.MP (Makefile:931 'acpithinkpad.o')