Hello
Not sure!
Apparently, after doing echo "0 blink" >/proc/acpi/ibm/led, this is handled led_set_status in drivers/platform/x86/thinkpad_acpi.c : the first argument is the led, the second the status :
acpi_evalf(led_handle, NULL, NULL, "vdd", led, led_led_arg1[ledstatus]))
For the LED string, see in led_init_detect_mode :
status = acpi_get_handle(ec_handle, "LED", &led_handle);
My understanding is that the OS does the call that correctly, but that coreboot ASL tables only expect one argument.
In coreboot/build/mainboard/lenovo/x60/dsdt.ramstage.asl, you will see Method (LED, 1, NotSerialized) which seems to confirm that, since in acpi-3.dsl I see instead Method (LED, 2, NotSerialized)