Re: [PATCH v2 1/1] x86: Use x2apic physical mode based on FADTsetting

From: Suresh Siddha
Date: Tue Apr 24 2012 - 21:42:56 EST


On Tue, 2012-04-24 at 18:23 -0600, Greg Pearson wrote:
> Provide systems that do not support x2apic cluster mode
> a mechanism to select x2apic physical mode using the
> FADT FORCE_APIC_PHYSICAL_DESTINATION_MODE bit.
>
> Changes from v1: (based on Suresh's comments)
> - removed #ifdef CONFIG_ACPI
> - removed #include <linux/acpi.h>
>
> Signed-off-by: Greg Pearson <greg.pearson@xxxxxx>
> ---
> arch/x86/kernel/apic/x2apic_phys.c | 6 ++++++
> 1 files changed, 6 insertions(+), 0 deletions(-)
>
> diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c
> index 8a778db..991e315 100644
> --- a/arch/x86/kernel/apic/x2apic_phys.c
> +++ b/arch/x86/kernel/apic/x2apic_phys.c
> @@ -24,6 +24,12 @@ static int x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
> {
> if (x2apic_phys)
> return x2apic_enabled();
> + else if ((acpi_gbl_FADT.header.revision >= FADT2_REVISION_ID) &&
> + (acpi_gbl_FADT.flags & ACPI_FADT_APIC_PHYSICAL) &&
> + x2apic_enabled()) {
> + printk(KERN_DEBUG "System requires x2apic physical mode\n");
> + return 1;
> + }
> else
> return 0;
> }

Acked-by: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>

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