From c04cb34725fdcf5fdb4135d8fdfaf6f318f10e99 Mon Sep 17 00:00:00 2001 From: Michael Chan Date: Mon, 7 May 2007 00:26:15 -0700 Subject: [PATCH] [TG3]: Eliminate spurious interrupts. Spurious interrupts are often encountered especially on systems using the 8259 PIC mode. This is because the I/O write to deassert the interrupt is posted and won't get to the chip immediately. As a result, the IRQ may remain asserted after the IRQ handler exits, causing spurious interrupts. Flush the interrupt mailbox in non-MSI handlers to de-assert the IRQ immediately. This seems to be the most straight forward approach after discussion with Jeff Garzik and David Miller. Signed-off-by: Michael Chan Signed-off-by: David S. Miller --- drivers/net/tg3.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c index 630c8a6..6f849bd 100644 --- a/drivers/net/tg3.c +++ b/drivers/net/tg3.c @@ -3590,8 +3590,12 @@ static irqreturn_t tg3_interrupt(int irq, void *dev_id) * Writing non-zero to intr-mbox-0 additional tells the * NIC to stop sending us irqs, engaging "in-intr-handler" * event coalescing. + * + * Flush the mailbox to de-assert the IRQ immediately to prevent + * spurious interrupts. The flush impacts performance but + * excessive spurious interrupts can be worse in some cases. */ - tw32_mailbox(MAILBOX_INTERRUPT_0 + TG3_64BIT_REG_LOW, 0x00000001); + tw32_mailbox_f(MAILBOX_INTERRUPT_0 + TG3_64BIT_REG_LOW, 0x00000001); if (tg3_irq_sync(tp)) goto out; sblk->status &= ~SD_STATUS_UPDATED; @@ -3635,8 +3639,12 @@ static irqreturn_t tg3_interrupt_tagged(int irq, void *dev_id) * writing non-zero to intr-mbox-0 additional tells the * NIC to stop sending us irqs, engaging "in-intr-handler" * event coalescing. + * + * Flush the mailbox to de-assert the IRQ immediately to prevent + * spurious interrupts. The flush impacts performance but + * excessive spurious interrupts can be worse in some cases. */ - tw32_mailbox(MAILBOX_INTERRUPT_0 + TG3_64BIT_REG_LOW, 0x00000001); + tw32_mailbox_f(MAILBOX_INTERRUPT_0 + TG3_64BIT_REG_LOW, 0x00000001); if (tg3_irq_sync(tp)) goto out; if (netif_rx_schedule_prep(dev)) { -- 2.7.4