Regarding Wake On USB input from S3 Sleep

[Dee Zay]

Dear FreeBSD ACPI Community,

I am trying to implement WakeOnUSB (e.g. USB keyboard input) from S3 Sleep
state, but have no clue where to start from.
I noticed the PS2 keyboard is capable of waking up a system and also found
there is a PS2 handler portion in asl from acpidump:

            Method (PS2K._PRW, 0, NotSerialized)  // _PRW: Power Resources
for Wake
            {
                Return (GPRW (0x6B, 0x03))
            }
However, there is no such handle for individual usb ports other than its
parent's class (\_SB_.PCI0.XHC_).
Also, I found there are FreeBSD-specific ACPICA C codes under /sys/dev
including acpi_button.c and acpi_lid.c, which are only for the fixed acpi
components.

So my question is,
Is it possible to implement WakeOnUSB input for individual USB ports by
somehow fixing the ACPICA C codes (without fixing the asl as it is
system-dependent)? If so, how?

I would really appreciate it if you could help me out here.

Best regards,
Julian