Does it actually work in a meaningful way on any hardware? In my testing, it still discharges the battery at about the same rate as leaving the OS up and turning the screen off, where Linux is about on par with Windows. But I might have a laptop the devs don't have access to, so I'm just left unsure where (if anywhere) it works as intended.
Yes, AFAIK it depends on the machine, on Intel at least there's debug output printed in the dmesg that should show if/how long it stays in different power states.
I think there is still work ongoing to improve battery life.
