Re: How to make an Intel EtherExpress known to xe(4)?

On Monday, 27 January 2003 at  0:01:31 +0100, Joerg Wunsch wrote:
> As Kevin Oberman wrote:
>
>> This is typical of receiving 802.1q tagged frames, but I have been
>> getting this error on my current system with a Xircom RE-100 card
>> and I am reasonably sure that i am not getting any tagged frames
>> where it's located.
>
> Me too.  The remote end is running a vx0 which i think couldn't
> even emit 802.1q tags at all.
>
> It's a bug in the driver, or an oddity of the xe hardware, depending
> on the point of view.  Unlike many other devices, it seems these chips
> do indeed deliver the FCS along with the packet, and set the length
> appropriately.
>
> Browsing through the source reveals that our network code could
> already handle this situation, only the driver needs to set the
> M_HASFCS flag.  The attached patch would do this.  If nobody objects,
> i'll commit that.
>
> The only remaining oddity is then that tcpdump displays the incoming
> packet (and length) including the FCS.
>
> I verified that the xe(4) driver in 4.x (where the card worked
> flawlessly so far) also experienced this behaviour, i. e. the upper
> network layers obviously silently ignored the trailing FCS.  Only now
> in 5.x, the kernel complains about oversized packets and discards
> them.

OK, I've tried this one, and it now works on my machine.  What would
be the implication of using this code with a card which doesn't return
the FCS?

Greg
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