When transferring data at full speed, the DM9000 network interface
sometimes stops sending/receiving data. Worse, ksoftirqd consumes
100% cpu and the net tx watchdog never triggers.
Fix by spin_lock_irqsave() in dm9000_start_xmit() to prevent the
interrupt handler from interfering.
Signed-off-by: Florian Westphal <[EMAIL PROTECTED]>
---
Actually the comments ('Disable all interrupts, iow(db, DM9000_IMR, IMR_PAR)
etc)
give the impression that the interrupt handler cannot run during
dm9000_start_xmit(),
however this isn't correct (perhaps the chipset has some weird timing issues?).
The interface lockup usually occurs between 30 and 360 seconds after starting
transmitting
data (netcat /dev/zero) at full speed; with this patch applied I haven't been
able
to reproduce hangs yet (ran for > 2h).
FTR: This is a dm9000 on XScale-PXA255 rev 6 (ARMv5TE)/Compulab CM-x255, i.e.
a module not supported by the vanilla kernel. Tested on (patched) 2.6.18.
dm9000.c | 25 +++++++------------------
1 file changed, 7 insertions(+), 18 deletions(-)
diff --git a/drivers/net/dm9000.c b/drivers/net/dm9000.c
index c3de81b..738aa59 100644
--- a/drivers/net/dm9000.c
+++ b/drivers/net/dm9000.c
@@ -700,6 +700,7 @@ dm9000_init_dm9000(struct net_device *dev)
static int
dm9000_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
+ unsigned long flags;
board_info_t *db = (board_info_t *) dev->priv;
PRINTK3("dm9000_start_xmit\n");
@@ -707,10 +708,7 @@ dm9000_start_xmit(struct sk_buff *skb, struct net_device
*dev)
if (db->tx_pkt_cnt > 1)
return 1;
- netif_stop_queue(dev);
-
- /* Disable all interrupts */
- iow(db, DM9000_IMR, IMR_PAR);
+ spin_lock_irqsave(&db->lock, flags);
/* Move data to DM9000 TX RAM */
writeb(DM9000_MWCMD, db->io_addr);
@@ -718,12 +716,9 @@ dm9000_start_xmit(struct sk_buff *skb, struct net_device
*dev)
(db->outblk)(db->io_data, skb->data, skb->len);
db->stats.tx_bytes += skb->len;
+ db->tx_pkt_cnt++;
/* TX control: First packet immediately send, second packet queue */
- if (db->tx_pkt_cnt == 0) {
-
- /* First Packet */
- db->tx_pkt_cnt++;
-
+ if (db->tx_pkt_cnt == 1) {
/* Set TX length to DM9000 */
iow(db, DM9000_TXPLL, skb->len & 0xff);
iow(db, DM9000_TXPLH, (skb->len >> 8) & 0xff);
@@ -732,23 +727,17 @@ dm9000_start_xmit(struct sk_buff *skb, struct net_device
*dev)
iow(db, DM9000_TCR, TCR_TXREQ); /* Cleared after TX complete */
dev->trans_start = jiffies; /* save the time stamp */
-
} else {
/* Second packet */
- db->tx_pkt_cnt++;
db->queue_pkt_len = skb->len;
+ netif_stop_queue(dev);
}
+ spin_unlock_irqrestore(&db->lock, flags);
+
/* free this SKB */
dev_kfree_skb(skb);
- /* Re-enable resource check */
- if (db->tx_pkt_cnt == 1)
- netif_wake_queue(dev);
-
- /* Re-enable interrupt */
- iow(db, DM9000_IMR, IMR_PAR | IMR_PTM | IMR_PRM);
-
return 0;
}
-
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