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>
git-mirror · Jul 8, 2008 · 60134eb · 60134eb
1 parent e67465f
commit 60134eb
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diff --git a/arch/x86/kernel/io_apic_32.c b/arch/x86/kernel/io_apic_32.c
@@ -2199,7 +2199,9 @@ static inline void __init check_timer(void)
 			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;
 		}

diff --git a/arch/x86/kernel/io_apic_64.c b/arch/x86/kernel/io_apic_64.c
@@ -1702,7 +1702,9 @@ static inline void __init check_timer(void)
 			apic_printk(APIC_VERBOSE," works.\n");
 			nmi_watchdog_default();
 			if (nmi_watchdog == NMI_IO_APIC) {
+				disable_8259A_irq(0);
 				setup_nmi();
+				enable_8259A_irq(0);
 			}
 			goto out;
 		}