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r8169: avoid losing MSI interrupts

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The 8169 chip only generates MSI interrupts when all enabled event
sources are quiescent and one or more sources transition to active. If
not all of the active events are acknowledged, or a new event becomes
active while the existing ones are cleared in the handler, we will not
see a new interrupt.

The current interrupt handler masks off the Rx and Tx events once the
NAPI handler has been scheduled, which opens a race window in which we
can get another Rx or Tx event and never ACK'ing it, stopping all
activity until the link is reset (ifconfig down/up). Fix this by always
ACK'ing all event sources, and loop in the handler until we have all
sources quiescent.

Signed-off-by: David Dillow <dave@thedillows.org>
Tested-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Dillow 2009-05-22 15:29:34 +00:00 • committed by David S. Miller
parent c80a5cdfc5
commit f11a377b3f
1 changed files with 62 additions and 50 deletions
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112
drivers/net/r8169.c
View file

@ -3554,54 +3554,64 @@ static irqreturn_t rtl8169_interrupt(int irq, void *dev_instance)
int handled = 0; int handled = 0;
int status; int status;
/* loop handling interrupts until we have no new ones or
* we hit a invalid/hotplug case.
*/
status = RTL_R16(IntrStatus); status = RTL_R16(IntrStatus);
while (status && status != 0xffff) {
handled = 1;
/* hotplug/major error/no more work/shared irq */ /* Handle all of the error cases first. These will reset
if ((status == 0xffff) || !status) * the chip, so just exit the loop.
goto out; */
if (unlikely(!netif_running(dev))) {
handled = 1; rtl8169_asic_down(ioaddr);
break;
if (unlikely(!netif_running(dev))) {
rtl8169_asic_down(ioaddr);
goto out;
}
status &= tp->intr_mask;
RTL_W16(IntrStatus,
(status & RxFIFOOver) ? (status | RxOverflow) : status);
if (!(status & tp->intr_event))
goto out;
/* Work around for rx fifo overflow */
if (unlikely(status & RxFIFOOver) &&
(tp->mac_version == RTL_GIGA_MAC_VER_11)) {
netif_stop_queue(dev);
rtl8169_tx_timeout(dev);
goto out;
}
if (unlikely(status & SYSErr)) {
rtl8169_pcierr_interrupt(dev);
goto out;
}
if (status & LinkChg)
rtl8169_check_link_status(dev, tp, ioaddr);
if (status & tp->napi_event) {
RTL_W16(IntrMask, tp->intr_event & ~tp->napi_event);
tp->intr_mask = ~tp->napi_event;
if (likely(napi_schedule_prep(&tp->napi)))
__napi_schedule(&tp->napi);
else if (netif_msg_intr(tp)) {
printk(KERN_INFO "%s: interrupt %04x in poll\n",
dev->name, status);
} }
/* Work around for rx fifo overflow */
if (unlikely(status & RxFIFOOver) &&
(tp->mac_version == RTL_GIGA_MAC_VER_11)) {
netif_stop_queue(dev);
rtl8169_tx_timeout(dev);
break;
}
if (unlikely(status & SYSErr)) {
rtl8169_pcierr_interrupt(dev);
break;
}
if (status & LinkChg)
rtl8169_check_link_status(dev, tp, ioaddr);
/* We need to see the lastest version of tp->intr_mask to
* avoid ignoring an MSI interrupt and having to wait for
* another event which may never come.
*/
smp_rmb();
if (status & tp->intr_mask & tp->napi_event) {
RTL_W16(IntrMask, tp->intr_event & ~tp->napi_event);
tp->intr_mask = ~tp->napi_event;
if (likely(napi_schedule_prep(&tp->napi)))
__napi_schedule(&tp->napi);
else if (netif_msg_intr(tp)) {
printk(KERN_INFO "%s: interrupt %04x in poll\n",
dev->name, status);
}
}
/* We only get a new MSI interrupt when all active irq
* sources on the chip have been acknowledged. So, ack
* everything we've seen and check if new sources have become
* active to avoid blocking all interrupts from the chip.
*/
RTL_W16(IntrStatus,
(status & RxFIFOOver) ? (status | RxOverflow) : status);
status = RTL_R16(IntrStatus);
} }
out:
return IRQ_RETVAL(handled); return IRQ_RETVAL(handled);
} }
@ -3617,13 +3627,15 @@ static int rtl8169_poll(struct napi_struct *napi, int budget)
if (work_done < budget) { if (work_done < budget) {
napi_complete(napi); napi_complete(napi);
tp->intr_mask = 0xffff;
/* /* We need for force the visibility of tp->intr_mask
* 20040426: the barrier is not strictly required but the * for other CPUs, as we can loose an MSI interrupt
* behavior of the irq handler could be less predictable * and potentially wait for a retransmit timeout if we don't.
* without it. Btw, the lack of flush for the posted pci * The posted write to IntrMask is safe, as it will
* write is safe - FR * eventually make it to the chip and we won't loose anything
* until it does.
*/ */
tp->intr_mask = 0xffff;
smp_wmb(); smp_wmb();
RTL_W16(IntrMask, tp->intr_event); RTL_W16(IntrMask, tp->intr_event);
} }