[PATCH] arm64: efi: add check for broken efi poweroff

[Shawn Guo]

+ Maximilian

On Fri, Mar 05, 2021 at 08:01:02AM +0100, Ard Biesheuvel wrote:
> On Fri, 5 Mar 2021 at 07:51, Shawn Guo <shawn.guo at linaro.org> wrote:
> >
> > Poweroff via UEFI Runtime Services doesn't always work on every single
> > arm64 machine.  For example, on Lenovo Flex 5G laptop, it results in
> > a system reboot rather than shutdown.  Add a DMI check to keep such
> > system stay with the original poweroff method (PSCI).
> >
> > Signed-off-by: Shawn Guo <shawn.guo at linaro.org>
> 
> What is the point of using EFI runtime services on this machine if
> poweroff doesn't work either? Can't we just boot this thing with
> efi=noruntime?

Ard,

With Maximilian playing ACPI kernel on Microsoft Surface Pro X, this
ResetSystem service issue triggers more discussion and testing [1].
Maximilian tested it with uefi-test-runner and reported that ResetSystem
actually works [2].

Looking at the kernel dump, I'm wondering if it's because that kernel
calls into the services with assuming they are in virtual addressing
mode, while actually they are in flat physical mode instead, due to
that SetVirtualAddressMap() call is skipped (efi_novamap).

Shawn

[1] https://github.com/Sonicadvance1/linux/issues/27#issuecomment-836103896
[2] https://github.com/Sonicadvance1/linux/issues/27#issuecomment-837184892