Commit 843a46f4 authored by Stephen Hemminger's avatar Stephen Hemminger

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
......@@ -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);
......
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