x86: keep MP_intsrc_info untouched if we do not update mptable

Daniel Exner reported IO-APIC enumeration breakage in linux-next.

Alexey Starikovskiy found out that it might be related to
commit 2944e16b25 "x86: update mptable".

use enable_update_mptable to decide if need check before add mp_irqs array.

Reported-by: Daniel Exner <webmaster@dragonslave.de>
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 0 deletions

diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c
index caf4ed7ca069..4d370b1c5ae8 100644
--- a/arch/x86/kernel/acpi/boot.c
+++ b/arch/x86/kernel/acpi/boot.c
@@ -1172,6 +1172,9 @@ int mp_config_acpi_gsi(unsigned char number, unsigned int devfn, u8 pin,
         struct mpc_config_intsrc intsrc;
         int ioapic;
 
+        if (!enable_update_mptable)
+                return 0;
+
         /* print the entry should happen on mptable identically */
         intsrc.mpc_type = MP_INTSRC;
         intsrc.mpc_irqtype = mp_INT;