[_V_]

Oh yeah, I've spent many hours on DELLs trying to solve S0ix sleep states... What a pain in the butt that is. There are few major pain points:

1) Every component has to be in the right "state of mind" in order for Si0x sleep to work properly. Do you have shitty NVMe that has buggy PCI powersaving? Too bad, battery will drain 10%/hour. Your yubikey keeps USB bus by constantly sending interrupts? Ha, enjoy your new backpack heater and watch out for fires...

2) It is extremely hard to debug these issues. I've figure out the yubikey and few things, but some of them are esoterical! ifconfig eth0 down = some part of Intel AMT stops sleeping and is now fully on all the time. Why? Because fck you, that's why. If you want to get some debug info, you can get some very cryptic state-flags for (some) components and you really have to guess what these really are - there is no documentation unfortunately.

3) UEFI is a mess - one would say that you want critical component, such as BIOS/boot chain to be as simple as possible and not* to be extensible in nature - because if some malicious code manages to get in the UEFI modules, you are simply hosed. But the other problem is that UEFI provides quite a lot of interfaces through ACPI and ACPI tables are buggy as hell. I had to patch DELL's DSDT tables in order to get back "deep" sleep - unfortunately it stopped working some time ago as they must have changed something somewehere and the computer would not wake up anymore... It is impossible to debug (or rather it is a royal pain to debug).