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Commit 843a46f4 authored by Stephen Hemminger's avatar Stephen Hemminger
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sky2: prevent dual port receiver problems 



When both ports are receiving simultaneously, the receive logic gets confused
and may pass up a packet before it is full. This causes hangs, and IP will see
lots of garbage packets. There is even the potential for data corruption if
a later arriving packet DMA's into freed memory.

It looks like a hardware bug because status arrives for a packet but no
data is there. Until this bug is worked out, block the user from bringing
up both ports at once.

Signed-off-by: default avatarStephen Hemminger <shemminger@osdl.org>
parent de54bc0f

drivers/net/sky2.c

+12 −1
Original line number Diff line number Diff line
@@ -1020,8 +1020,19 @@ static int sky2_up(struct net_device *dev) 
	struct sky2_hw *hw = sky2->hw;

	unsigned port = sky2->port;

	u32 ramsize, rxspace, imask;

	int err = -ENOMEM;

	int err;

	struct net_device *otherdev = hw->dev[sky2->port^1];



	/* Block bringing up both ports at the same time on a dual port card.

	 * There is an unfixed bug where receiver gets confused and picks up

	 * packets out of order. Until this is fixed, prevent data corruption.

	 */

	if (otherdev && netif_running(otherdev)) {

		printk(KERN_INFO PFX "dual port support is disabled.\n");

		return -EBUSY;

	}



	err = -ENOMEM;

	if (netif_msg_ifup(sky2))

		printk(KERN_INFO PFX "%s: enabling interface\n", dev->name);