[BNX2]: Reduce spurious INTA 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.
Add read back to flush the I/O write to deassert the IRQ immediately.
We also store the last_status_idx immediately in the IRQ handler to
help detect whether the interrupt is ours or not when the IRQ is
entered again before ->poll gets called.
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bnx2.c b/drivers/net/bnx2.c
index 439f482..a806a8e 100644
--- a/drivers/net/bnx2.c
+++ b/drivers/net/bnx2.c
@@ -2547,6 +2547,7 @@
{
struct net_device *dev = dev_instance;
struct bnx2 *bp = netdev_priv(dev);
+ struct status_block *sblk = bp->status_blk;
/* When using INTx, it is possible for the interrupt to arrive
* at the CPU before the status block posted prior to the
@@ -2554,7 +2555,7 @@
* When using MSI, the MSI message will always complete after
* the status block write.
*/
- if ((bp->status_blk->status_idx == bp->last_status_idx) &&
+ if ((sblk->status_idx == bp->last_status_idx) &&
(REG_RD(bp, BNX2_PCICFG_MISC_STATUS) &
BNX2_PCICFG_MISC_STATUS_INTA_VALUE))
return IRQ_NONE;
@@ -2563,11 +2564,19 @@
BNX2_PCICFG_INT_ACK_CMD_USE_INT_HC_PARAM |
BNX2_PCICFG_INT_ACK_CMD_MASK_INT);
+ /* Read back to deassert IRQ immediately to avoid too many
+ * spurious interrupts.
+ */
+ REG_RD(bp, BNX2_PCICFG_INT_ACK_CMD);
+
/* Return here if interrupt is shared and is disabled. */
if (unlikely(atomic_read(&bp->intr_sem) != 0))
return IRQ_HANDLED;
- netif_rx_schedule(dev);
+ if (netif_rx_schedule_prep(dev)) {
+ bp->last_status_idx = sblk->status_idx;
+ __netif_rx_schedule(dev);
+ }
return IRQ_HANDLED;
}