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: Stephen Hemminger <shemminger@osdl.org>
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1 changed files with 12 additions and 1 deletions
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@ -1020,8 +1020,19 @@ static int sky2_up(struct net_device *dev)
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struct sky2_hw *hw = sky2->hw;
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unsigned port = sky2->port;
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u32 ramsize, rxspace, imask;
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int err = -ENOMEM;
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int err;
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struct net_device *otherdev = hw->dev[sky2->port^1];
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/* Block bringing up both ports at the same time on a dual port card.
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* There is an unfixed bug where receiver gets confused and picks up
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* packets out of order. Until this is fixed, prevent data corruption.
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*/
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if (otherdev && netif_running(otherdev)) {
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printk(KERN_INFO PFX "dual port support is disabled.\n");
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return -EBUSY;
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}
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err = -ENOMEM;
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if (netif_msg_ifup(sky2))
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printk(KERN_INFO PFX "%s: enabling interface\n", dev->name);
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