leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

[BNX2]: Reduce spurious INTA interrupts.

Browse Source 
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>
This commit is contained in:
Michael Chan 2007-07-07 22:51:03 -07:00 committed by David S. Miller
parent 9b1084b8f9
commit b8a7ce7bed
1 changed files with 11 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/net/bnx2.c
View File

@ -2547,6 +2547,7 @@ bnx2_interrupt(int irq, void *dev_instance)
{
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 @@ bnx2_interrupt(int irq, void *dev_instance)
* 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_interrupt(int irq, void *dev_instance)
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;
}