Some success with laptop sleep (ACPI S3)

[coypu%SDF.ORG@localhost]

Hello, I know a lot of people have been unable to put their laptops to
sleep and wake them back up.
I've had marginally more success with it and can do a sleep-wake cycle
once with my machine with the following changes:
sysctl -w hw.acpi.sleep.vbios=2 (Needed for when you have DRMKMS)
sysctl -w hw.acpi.sleep.state=3 (Put it to sleep)

Some trouble I've had:
Sometimes it doesn't fully wake up.
This is less likely with Xorg running, and once I've woken it up with
ssh from another machine.

Sleep a second time:
This either doesn't work (it will revert the changes), or it will go
into an intermediate mode. 
In this intermediate mode, waking the laptop up with power plugged in
will do nothing. with no power plugged in, it will reboot.

It's progress!
Please attempt the same on your laptops if possible.

I've filed this as port-amd64/50733.
Link for the lazy: http://gnats.netbsd.org/50733

coypu.