[U-Boot] [PATCH v1 7/7] x86: acpi: Don't touch hardware on HW reduced platforms

[Bin Meng]

Hi Andy,

On Sat, Jul 22, 2017 at 3:32 AM, Andy Shevchenko
<andriy.shevchenko at linux.intel.com> wrote:
> If ACPI HW reduced bit in FADT is set we should ignore any ACPI hardware
> communications.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko at linux.intel.com>
> ---
>  arch/x86/lib/acpi_table.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/arch/x86/lib/acpi_table.c b/arch/x86/lib/acpi_table.c
> index da6014fb41..3eb101105b 100644
> --- a/arch/x86/lib/acpi_table.c
> +++ b/arch/x86/lib/acpi_table.c
> @@ -463,6 +463,10 @@ ulong write_acpi_tables(ulong start)
>
>         debug("ACPI: done\n");
>
> +       /* Don't touch ACPI hardware on HW reduced platforms */
> +       if (fadt->flags & ACPI_FADT_HW_REDUCED_ACPI)
> +               return current;
> +

Reviewed-by: Bin Meng <bmeng.cn at gmail.com>

I assume this is needed on Intel Edison. If that's the case, will you
support S3 resume on Edison? And if yes, I believe we will need update
acpi_resume() to add the same check there?

>         /*
>          * Other than waiting for OSPM to request us to switch to ACPI mode,
>          * do it by ourselves, since SMI will not be triggered.
> --

Regards,
Bin