From: Aaro Koskinen <aaro.koskinen@iki.fi>
Date: Wed, 27 Mar 2019 22:35:34 +0200

I accidentally had MTU size mismatch (9000 vs. 1500) in my network,
and I noticed I could kill a system using stmmac & 1500 MTU simply
by pinging it with "ping -s 2000 ...".

While testing a fix I encountered also some other issues that need fixing.

I have tested these only with enhanced descriptors, so the normal
descriptor changes need a careful review.

I really want to see some stmmac developers review and/or test these
changes.

Thanks.