[PATCH] Do not enforce unique IO_APIC_ID check for xAPIC systems (i386)

This patch is per Andi's request to remove NO_IOAPIC_CHECK from genapic and
use heuristics to prevent unique I/O APIC ID check for systems that don't
need it.  The patch disables unique I/O APIC ID check for Xeon-based and
other platforms that don't use serial APIC bus for interrupt delivery.
Andi stated that AMD systems don't need unique IO_APIC_IDs either.

Signed-off-by: Natalie Protasevich <Natalie.Protasevich@unisys.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/arch/i386/kernel/mpparse.c b/arch/i386/kernel/mpparse.c
index 1347ab4939e7..0a061056b828 100644
--- a/arch/i386/kernel/mpparse.c
+++ b/arch/i386/kernel/mpparse.c
@@ -914,7 +914,10 @@ void __init mp_register_ioapic (
         mp_ioapics[idx].mpc_apicaddr = address;
 
         set_fixmap_nocache(FIX_IO_APIC_BASE_0 + idx, address);
-        mp_ioapics[idx].mpc_apicid = io_apic_get_unique_id(idx, id);
+        if ((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 < 15))
+                mp_ioapics[idx].mpc_apicid = io_apic_get_unique_id(idx, id);
+        else
+                mp_ioapics[idx].mpc_apicid = id;
         mp_ioapics[idx].mpc_apicver = io_apic_get_version(idx);
         
         /*