From: "Zhang, Yanmin" On my IA64 machine, after kernel 2.6.12-rc3 boots, an edge-triggered interrupt (IRQ 46) keeps triggered over and over again. There is no IRQ 46 interrupt action handler. It has lots of impact on performance. Kernel 2.6.10 and its prior versions have no the problem. Basically, kernel 2.6.10 will mask the spurious edge interrupt if the interrupt is triggered for the second time and its status includes IRQ_DISABLE|IRQ_PENDING. Originally, IA64 kernel has its own specific _irq_desc definitions in file arch/ia64/kernel/irq.c. The definition initiates _irq_desc[irq].status to IRQ_DISABLE. Since kernel 2.6.11, it was moved to architecture independent codes, i.e. kernel/irq/handle.c, but kernel/irq/handle.c initiates _irq_desc[irq].status to 0 instead of IRQ_DISABLE. Signed-off-by: Zhang Yanmin Signed-off-by: Andrew Morton --- kernel/irq/handle.c | 1 + 1 files changed, 1 insertion(+) diff -puN kernel/irq/handle.c~spurious-interrupt-fix kernel/irq/handle.c --- 25/kernel/irq/handle.c~spurious-interrupt-fix 2005-05-15 21:33:07.000000000 -0700 +++ 25-akpm/kernel/irq/handle.c 2005-05-15 21:33:07.000000000 -0700 @@ -30,6 +30,7 @@ */ irq_desc_t irq_desc[NR_IRQS] __cacheline_aligned = { [0 ... NR_IRQS-1] = { + .status = IRQ_DISABLED, .handler = &no_irq_type, .lock = SPIN_LOCK_UNLOCKED } _