>Number:         11175
>Category:       port-next68k
>Synopsis:       dma panic after ethernet `discarding oversize frame' error
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    port-next68k-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Oct 09 02:31:00 PDT 2000
>Closed-Date:
>Last-Modified:
>Originator:     Darrin B. Jewell
>Release:        -current ~20001007T0926Z
>Organization:
	
>Environment:
	mourning, a mono next68k slab.

>Description:
        in the bootup sequence, the machine will panic in the nextdma
driver with a dma register dump and the error:
"panic: DMA: Unexpected registers in finish_xfer"

previous to this error, there is the message
"xe0: discarding oversize frame"
which I believe is a recently added check to the ether_input routine
in src/sys/net/if_ethersubr.c

This is repeatable, it appears to occur each time I boot
and immediately after the normal boot up message:
"Automatic boot in progress: starting file system checks"

>How-To-Repeat:
        netboot a current GENERIC kernel
>Fix:
I suspect there are two problems here, I don't know how much
they are intertwined.
 1. The ethernet driver is passing a something bogus to ether_input()
 2. the dma driver is failing to recover from this error condition.


>Release-Note:
>Audit-Trail:
>Unformatted: