Kevin Hilman <[email protected]> writes: > [email protected] writes: > >> From: Sneha Narnakaje <[email protected]> >> >> This patch fixes the NETDEV WATCHDOG timeout issue with dm9000 ethernet >> driver on DM355, while using the NFS as root filesystem. >> In the patch I have replaced the spin_lock/spin_unlock calls with dm9000 >> specific disable/enable interrupt calls, in the dm9000 hard_start_xmit >> routine. Though it seems to be a generic issue discussed in the netdev list, >> this fix may not be a permanent solution, yet we can proceed with other >> drivers >> on DM355. >> I have also enabled the dm9000 option in the DM355 default configuration. >> [ ... ]
>> --- a/drivers/net/dm9000.c >> +++ b/drivers/net/dm9000.c >> @@ -758,7 +758,8 @@ dm9000_start_xmit(struct sk_buff *skb, struct net_device >> *dev) >> if (db->tx_pkt_cnt > 1) >> return 1; >> >> - spin_lock_irqsave(&db->lock, flags); >> + /* Disable all interrupts */ >> + iow(db, DM9000_IMR, IMR_PAR); > > I didn't look at all the locking in this driver, but for correctness, > I'm guessing you probably need to do the dm9000-specific disable in > addition to the spin_lock. That way you only add the extra interrupt > disable, and don't change the locking. > In otherwords, see patch below which goes on top of yours. It keeps the locking intact. Together with yours, it basically replaces the global IRQ disable with a dm9000 only IRQ disable. The question still remains... what is different about the global IRQ disable compared to the dm9000-only IRQ disable. The other difference I can think of between this and is being replaced: If the xmit function is called with interrupts disabled, your patch ensures that interrupts are (re)enabled when xmit finishes. If interrupts are disabled when xmit is entered, it will exit with them disabled as well due to the restore. To see if that is happening, you might try to throw a 'WARN_ON(irqs_disabled());' in the xmit function in the original version (before your patch.) Kevin commit f0a524a6bd7900556a35dcc53f3a493576ba742c Author: Kevin Hilman <[email protected]> Date: Tue Feb 10 21:04:57 2009 -0800 NET: dm9000: re-add spinlock, but without IRQ save/restore diff --git a/drivers/net/dm9000.c b/drivers/net/dm9000.c index 90e3fd6..20ded42 100644 --- a/drivers/net/dm9000.c +++ b/drivers/net/dm9000.c @@ -750,7 +750,6 @@ static void dm9000_timeout(struct net_device *dev) static int dm9000_start_xmit(struct sk_buff *skb, struct net_device *dev) { - unsigned long flags; board_info_t *db = netdev_priv(dev); dm9000_dbg(db, 3, "%s:\n", __func__); @@ -761,6 +760,8 @@ dm9000_start_xmit(struct sk_buff *skb, struct net_device *dev) /* Disable all interrupts */ iow(db, DM9000_IMR, IMR_PAR); + spin_lock(&db->lock); + /* Move data to DM9000 TX RAM */ writeb(DM9000_MWCMD, db->io_addr); @@ -784,6 +785,8 @@ dm9000_start_xmit(struct sk_buff *skb, struct net_device *dev) netif_stop_queue(dev); } + spin_unlock(&db->lock); + /* Re-enable interrupt */ iow(db, DM9000_IMR, IMR_PAR | IMR_PTM | IMR_PRM); _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
