[Firmware Bug]: [0.096072] No firmware reserved region can cover this message at boot with kernel 5.13.2

With every boot of NixOS on the Surface Pro 3, so Intel HaswelI Graphics/CPU I get this error. Both kernel 5.13.2 and 5.12.7 too produce it, with UEFI being in use here:

I know this message is quite vague, but on Arch, also with the current 5.13 kernel I don’t get any such error.

I wonder what’d be the difference between those? I suspect thermals, a GPU driver, or some kernel module (related to Intel? maybe?) could be the culprit here? But what exactly? And why NixOS specifically? I have no idea…

Downgrading to kernel 4.19 fixes the problem for now.

Reported upstream here, here, here & here.

Possible cause: the new ACPI implementation?

Current status: Awaiting a fix, or workaround