Built in PS2 keyboard in new ASUS/acer laptops can not wake up system after s2idle

[Chris Chiu]

Hi guys,
    We have some new laptops with Intel new Intel WiskyLake CPU come
in and they all have the same problem. They all have the so-called
"Modern Standby" feature which is s2idle in Linux.

    The problem is the built-in keyboard no longer wake up the system
after it goes to s2idle. Only the power button can wake up. It's
different from the other laptops with old Intel CPUs (CoffeeLake,
KaybeLake...etc). We found the difference is that the EC (embedded
controller) no longer signals SCI event when in s2idle.

    Confirmed with ASUS EC engineer, he also admits that the EC code
for signaling SCI event in modern standby has been removed on
WiskyLake models. Because the built-in PS2 keyboard can still wake up
the system on WisksyLake+Windows10 RS4 combination without EC
intervention.

    Based on this information, we suspect that maybe the built-in
keyboard wakeup on Windows 10 RS4 in enabled by default (although we
don't know how to prove that). It's easy to simply do
'device_set_wakeup_enable' and 'enable_irq_wake' for the i8042
keyboard port to wake up the system without EC, but it's nasty.

    Any suggestion about how to achieve the keyboard wake up function
on these new laptops in a generic way? Thanks

Chris