S0i3 sleep testing image

Hia everyone!

I am currently working on S0i3 support for FreeBSD, and I have
prepared a sleep testing image to make it easier to test this on a
wide variety of different hardware. You can find these images here:

https://people.freebsd.org/~obiwac/s0ix/

They are expected to successfully enter S0i3 on 7040 series AMD
processors, and may work on a wider variety of (AMD) machines (I do
not expect this to work out of the box on Intel, but I have never
tried this out). Instructions about how to read the S0i3 entry metrics
are available in the /root/README file or on that page.

You can also of course build the kernel yourself instead:

https://github.com/obiwac/freebsd-s0ix/tree/everything

If you are interested in trying this out for yourself, it would be
great if you could send me the ACPI dump of your machine (acpidump
-dt) as well as the SMU metrics sysctl tree on AMD (sysctl
dev.amdsmu.0).

Thanks!
Aymeric