Re: EFI reboot vs. ACPI reboot (was: Re: [tip:x86/urgent] x86/reboot, efi: Use EFI reboot for Acer TravelMate X514-51T)

[Daniel Drake]

On Tue, Apr 16, 2019 at 4:20 PM Ingo Molnar <mingo@xxxxxxxxxx> wrote:
> I wanted to get a second opinion from the EFI folks for this whole
> concept. On x86 we default to ACPI reboot on modern systems, and we
> default to EFI reboot on modern EFI systems, via the
> efi_reboot_required() method which keys off on acpi_gbl_reduced_hardware
> to create a barrier for older ACPI systems.

So if acpi_gbl_reduced_hardware is set, we are on a "modern EFI
system", and EFI reboot is used.

> It appears that Acer TravelMate X514-51T systems get marked as
> 'acpi_gbl_reduced_hardware' which enables ACPI-reboot, but they require
> EFI-reboot.

We will double check, but in this case I believe the system is *not*
marked as reduced hardware, which is why ACPI reboot is used.

> Should we perhaps re-think the boundary between EFI-reboot and
> ACPI-reboot systems? I.e. if the EFI runtime is enabled, shouldn't we
> just use the EFI reboot method?

I agree this is a good question.

We also previously hit a similar issue for shutdown on Acer laptops
which is still unresolved.
https://marc.info/?l=linux-acpi&m=148857214431346&w=2

Daniel