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

[Ard Biesheuvel <ardb@kernel.org>]

On Fri, 5 Mar 2021 at 07:51, Shawn Guo <shawn.guo@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@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?


> ---
>  arch/arm64/kernel/efi.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
>
> diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
> index fa02efb28e88..8ae0002c72f1 100644
> --- a/arch/arm64/kernel/efi.c
> +++ b/arch/arm64/kernel/efi.c
> @@ -7,6 +7,7 @@
>   * Copyright (C) 2013, 2014 Linaro Ltd.
>   */
>
> +#include <linux/dmi.h>
>  #include <linux/efi.h>
>  #include <linux/init.h>
>
> @@ -113,12 +114,26 @@ int __init efi_set_mapping_permissions(struct mm_struct *mm,
>                                    set_permissions, md);
>  }
>
> +static const struct dmi_system_id efi_reboot_broken_table[] = {
> +       {
> +               .ident = "Lenovo Flex 5G",
> +               .matches = {
> +                       DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> +                       DMI_MATCH(DMI_PRODUCT_FAMILY, "Flex 5G"),
> +               },
> +       },
> +       { } /* terminator */
> +};
> +
>  /*
>   * UpdateCapsule() depends on the system being shutdown via
>   * ResetSystem().
>   */
>  bool efi_poweroff_required(void)
>  {
> +       if (dmi_check_system(efi_reboot_broken_table))
> +               return false;
> +
>         return efi_enabled(EFI_RUNTIME_SERVICES);
>  }
>
> --
> 2.17.1
>