[Follow-up] Quest of enabling hotkeys on ASUS Laptops

Resuming for the previous topic, with the help of an Arch user and one of kernel maintainers, it turned out the failure of hotkeys functions [Fn] is due to a Linux ACPI bug. Further investigation revealed a bad practice from BIOS vendor and unexpectedly a new challenge in Linux kernel world as quoted:

However this report indicates us another gap (except the enumeration order gap):
If the namespace EC (DSDT EC in short) is not ready, EC access availability can be kept 
using the ECDT EC. In Linux, that requres _Qxx control methods to be registered for
the ECDT EC. I have never seen a Linux EC driver version doing this before,
_Qxx registration is only invoked in acpi_ec_add(). So this bug indicates a gap for Linux.

Essentially, what is initially a bug related for non-functional hotkeys for ASUS X550Z laptop revealed a much more deeper issue related Linux ACPI. It is the first time I reached that level of testing in kernel world with the help from upstream kernel.

A built kernel with an attempt patch to resolve ACPI EC problem is on COPR repository. It willl take longer to complete before testing the patch which will hopefully restore hotkeys functionality on some modern laptops especially ASUS. A suivre...