From ea0dcf903e7d76aa5d483d876215fedcfdfe140f Mon Sep 17 00:00:00 2001
From: Greg Pearson <greg.pearson@hp.com>
Date: Tue, 24 Apr 2012 18:23:56 -0600
Subject: [PATCH] x86/apic: Use x2apic physical mode based on FADT setting
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@hp.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Link: http://lkml.kernel.org/r/1335313436-32020-1-git-send-email-greg.pearson@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/kernel/apic/x2apic_phys.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c
index 8a778db45e3a..991e315f4227 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;
}
--
2.34.1