S3 emulation via s0ix in newer BIOSes that no longer support S3

[zachs78]

It appears that newer laptops have started removing support for S3 altogether in favor of the new s0ix implementation in new Intel CPUs.

FreeBSD had a commit in 2018 that specifically adds S3 emulation for systems that have buggy S3, slow S3 or no S3 altogether https://github.com/bwidawsk/freebsd/commit/65a58f63023602e1cb59a690eb9d6cdebb466a02

 

Any ideas how this might be possible in OpenCore, short of hacking the MacOS kernel itself?

 

Perhaps recompiling the Darwin kernel, patching the asm function acpi_sleep_cpu() passing in an emulated S3 ala the freeBSD commit might work. But we'll need to swap the Darwin kernel out from official Mac OS install though.

 

EDIT: Just to clarify my idea, this would only work if we can somehow poll the power button to "resume". We sit in a tight loop calling cpu_mwait() which prevents the rest of the system from working, keeping CPU in low power mode which is a poor man's S3. All your peripherals would still be powered, but at least the CPU won't suddenly wake up and start a fire in your bag while fake sleeping. Perhaps Microsoft should steal this and implement it in their NT Kernel.

Edited September 22, 2020 by zachs78