[PATCH] arm64: acpi: add a Kconfig option to prefer ACPI boot over DT

[Roy Franz]

On Mon, Apr 11, 2016 at 5:01 AM, Graeme Gregory
<graeme.gregory at linaro.org> wrote:
> On Mon, Apr 11, 2016 at 01:19:28PM +0200, Ard Biesheuvel wrote:
>> If both ACPI and DT platform descriptions are available, and the
>> kernel was configured at build time to support both flavours, the
>> default policy in absence of a acpi=[off|force] kernel command line
>> parameter is to prefer DT over ACPI.
>>
>> This adds an option to invert that default policy, and prefer ACPI
>> over DT instead. Note that this policy is still superseded by the
>> value of the acpi= command line parameter.
>>
>
> Looks sane to me
>
> Reviewed-by: Graeme Gregory <graeme.gregory at linaro.org>
>
> G
>
Reviewed-by: Roy Franz <roy.franz at hpe.com>


>> Signed-off-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>
>> ---
>>  arch/arm64/Kconfig       | 13 +++++++++++++
>>  arch/arm64/kernel/acpi.c |  3 ++-
>>  2 files changed, 15 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>> index 4f436220384f..f3aef40ad0ac 100644
>> --- a/arch/arm64/Kconfig
>> +++ b/arch/arm64/Kconfig
>> @@ -918,6 +918,19 @@ config DMI
>>         However, even with this option, the resultant kernel should
>>         continue to boot on existing non-UEFI platforms.
>>
>> +config PREFER_ACPI_OVER_DT
>> +     bool "Prefer booting via ACPI if both ACPI and DT are available"
>> +     depends on ACPI
>> +     help
>> +       If both ACPI and DT platform descriptions are available, and the
>> +       kernel was configured at build time to support both flavours, the
>> +       default policy in absence of a acpi=[off|force] kernel command line
>> +       parameter is to prefer DT over ACPI.
>> +
>> +       This option inverts that default policy, by preferring ACPI over DT
>> +       instead. Note that this default policy is still superseded by the
>> +       value of the acpi= command line parameter.
>> +
>>  endmenu
>>
>>  menu "Userspace binary formats"
>> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
>> index d1ce8e2f98b9..50ac056fb1fd 100644
>> --- a/arch/arm64/kernel/acpi.c
>> +++ b/arch/arm64/kernel/acpi.c
>> @@ -188,7 +188,8 @@ void __init acpi_boot_table_init(void)
>>        *   and ACPI has not been force enabled (acpi=force)
>>        */
>>       if (param_acpi_off ||
>> -         (!param_acpi_force && of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
>> +         (!IS_ENABLED(CONFIG_PREFER_ACPI_OVER_DT) &&
>> +          !param_acpi_force && of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
>>               return;
>>
>>       /*
>> --
>> 2.5.0
>>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel