x86: I/O APIC: keep IRQ off when changing LVT registers
Disable the 8259A acting in the "virtual wire" mode to keep the interrupt
line inactive while fiddling with local APIC interrupt vector registers
associated with its destination inputs. To be on the safe side,
especially concerning flipping the trigger mode.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/io_apic_32.c b/arch/x86/kernel/io_apic_32.c
index e7b7655..41218ac 100644
--- a/arch/x86/kernel/io_apic_32.c
+++ b/arch/x86/kernel/io_apic_32.c
@@ -2199,7 +2199,9 @@
else
add_pin_to_irq(0, apic2, pin2);
if (nmi_watchdog == NMI_IO_APIC) {
+ disable_8259A_irq(0);
setup_nmi();
+ enable_8259A_irq(0);
}
goto out;
}