kern/46365: alc can't relink after cable disconnect

[diro%nixsyspaus.org@localhost]

>Number:         46365
>Category:       kern
>Synopsis:       alc can't relink after cable disconnect
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Apr 23 14:10:00 +0000 2012
>Originator:     diro%nixsyspaus.org@localhost
>Release:        NetBSD 6.0_BETA
>Organization:
>Environment:
System: NetBSD gift 6.0_BETA NetBSD 6.0_BETA (GIFT) #4: Sat Mar 24 19:39:43 UTC 
2012  root@gift:/usr/obj/sys/arch/amd64/compile/GIFT amd64
Architecture: amd64
Machine: amd64
>Description:

Can't access network after disconnecting and reconnecting network cable. Link 
light glows, turns off, then turns back on again. This process repeats without 
any connection to the network (router) or another machine connected directly. 
In the console log:

Apr 23 12:15:47 gift /netbsd: alc0: DMA write error! -- resetting

repeated. Also, randomly repeated in the console log (possibly related):

Apr 23 06:12:43 gift /netbsd: alc0: watchdog timeout (missed link)

>How-To-Repeat:

dmesg | grep alc0
alc0 at pci1 dev 0 function 0: Atheros AR8131 PCIe Gigabit Ethernet
alc0: interrupting at ioapic0 pin 16
alc0: Ethernet address 00:26:9e:b3:b2:ec
atphy0 at alc0 phy 0: L1 10/100/1000 PHY, rev. 11


>Fix: