Hi Eric,
On Tue, Nov 22, 2016 at 08:09:58AM -0800, Eric Dumazet wrote:
Looks like there's a few similarly named devices and drivers. Mine is
an SMSC LAN91C111 using the smc91x driver in
drivers/net/ethernet/smsc/smc91x.c, rather than smc911x.c. So the
interrupt handler is smc_interrupt()
CONFIG_ARCH_PXA is not set, nor is SMC_USE_PXA_DMA or SMC_USE_DMA.
Oh right.
static irqreturn_t smc_interrupt(int irq, void *dev_id)
{
...
mask = SMC_GET_INT_MASK(lp);
SMC_SET_INT_MASK(lp, 0);
loop()
...
} else if (status & IM_ALLOC_INT) {
DBG(3, dev, "Allocation irq\n");
tasklet_hi_schedule(&lp->tx_task);
mask &= ~IM_ALLOC_INT;
}
...
SMC_SET_INT_MASK(lp, mask);
spin_unlock(&lp->lock);
/*
* We return IRQ_HANDLED unconditionally here even if there was
* nothing to do. There is a possibility that a packet might
* get enqueued into the chip right after TX_EMPTY_INT is raised
* but just before the CPU acknowledges the IRQ.
* Better take an unneeded IRQ in some occasions than complexifying
* the code for all cases.
*/
return IRQ_HANDLED;
}
Could you trace mask value, it looks we loop and never acknowledge
some interrupt status.
Maybe driver depends on tasklet_hi_schedule() triggers
smc_hardware_send_pkt() really really soon.
Oh, but smc_hardware_send_pkt() uses a spin_trylock() at its
beginning, then later a spin_lock() hidden in SMC_ENABLE_INT(),
this looks racy.
This patch didn't help.
I did get some new traces though - I've attached the diff for the
trace_printks I added.
Before 4cd13c21b207:
https://drive.google.com/open?id=0B8siaK6ZjvEwcEtOeFQzTmY0Nnc
After 4cd13c21b207:
https://drive.google.com/open?id=0B8siaK6ZjvEwZnQ4MVg1d3d1Tm8
It looks like the difference is that after 4cd13c21b207 the RX softirq
isn't running, and RX interrupts don't call softirq_raise anymore -
presumably because there's one pending, but I didn't have time to
track that down to a code-path.
Cheers,
-Brian
--->8---
diff --git a/drivers/net/ethernet/smsc/smc91x.c
b/drivers/net/ethernet/smsc/smc91x.c
index 503a3b6..6598319 100644
--- a/drivers/net/ethernet/smsc/smc91x.c
+++ b/drivers/net/ethernet/smsc/smc91x.c
@@ -418,7 +418,7 @@ static inline void smc_rcv(struct net_device *dev)
packet_number = SMC_GET_RXFIFO(lp);
if (unlikely(packet_number & RXFIFO_REMPTY)) {
- PRINTK(dev, "smc_rcv with nothing on FIFO.\n");
+ trace_printk("smc_rcv with nothing on FIFO.\n");
return;
}
@@ -475,6 +475,7 @@ static inline void smc_rcv(struct net_device *dev)
SMC_WAIT_MMU_BUSY(lp);
SMC_SET_MMU_CMD(lp, MC_RELEASE);
dev->stats.rx_dropped++;
+ trace_printk("rx_dropped.\n");
return;
}
@@ -1216,7 +1217,7 @@ static irqreturn_t smc_interrupt(int irq, void *dev_id)
int status, mask, timeout, card_stats;
int saved_pointer;
- DBG(3, dev, "%s\n", __func__);
+ trace_printk("%s\n", __func__);
spin_lock(&lp->lock);
@@ -1235,7 +1236,7 @@ static irqreturn_t smc_interrupt(int irq, void *dev_id)
do {
status = SMC_GET_INT(lp);
- DBG(2, dev, "INT 0x%02x MASK 0x%02x MEM 0x%04x FIFO 0x%04x\n",
+ trace_printk("INT 0x%02x MASK 0x%02x MEM 0x%04x FIFO 0x%04x\n",
status, mask,
({ int meminfo; SMC_SELECT_BANK(lp, 0);
meminfo = SMC_GET_MIR(lp);
@@ -1254,7 +1255,7 @@ static irqreturn_t smc_interrupt(int irq, void *dev_id)
if (THROTTLE_TX_PKTS)
netif_wake_queue(dev);
} else if (status & IM_RCV_INT) {
- DBG(3, dev, "RX irq\n");
+ trace_printk("RX irq\n");
smc_rcv(dev);
} else if (status & IM_ALLOC_INT) {
DBG(3, dev, "Allocation irq\n");
@@ -1304,7 +1305,7 @@ static irqreturn_t smc_interrupt(int irq, void *dev_id)
PRINTK(dev, "spurious interrupt (mask = 0x%02x)\n",
mask);
#endif
- DBG(3, dev, "Interrupt done (%d loops)\n",
+ trace_printk("Interrupt done (%d loops)\n",
MAX_IRQ_LOOPS - timeout);
/*
