From: Stephen Hemminger Date: Thu, 11 May 2006 22:07:28 +0000 (-0700) Subject: sky2: prevent dual port receiver problems X-Git-Tag: firefly_0821_release~35762^2 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=843a46f423a508b3a443a08baa903c6da02f3297;p=firefly-linux-kernel-4.4.55.git 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 --- diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c index ffd267fab21d..62be6d99d05c 100644 --- a/drivers/net/sky2.c +++ b/drivers/net/sky2.c @@ -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);