11.2-RC3 regression - networking igb driver

[Jim Pingle]

On 6/23/2018 1:27 PM, David Samms wrote:
> There is a regression in 11.2-RC3 that effects the igb driver for Intels
> C2000 SoC I354 Quad GbE Controller
> 
> Supermicro A1SRi-2558F
> http://www.supermicro.com/products/motherboard/Atom/X10/A1SRi-2558F.cfm
> 
> This server has run 10.x and 11.x fine up till 11.2-RC3.
> 
> PROBLEM:
> with 11.2-RC3 the server boots and gets a network connection to the
> cable modem, but the interface (igb0) resets every 4-8 second. The reset
> time appears to be related to network load, but reset withing 10s with
> next to no traffic. I did try swapping cables, but with no effect. With
> each reset the interface successfully obtains an IP address via DHCP,
> works for a few seconds and resets.
> 
> Restoring the server to 11.1-RELEASE-p10 resolves the problem.
> 
> Any suggestions?

Does your DHCP server send you an MTU, perhaps? Before the interface
resets, what does its MTU show?

You might try creating a dhclient.conf that sets "supersede
interface-mtu 0;" and see if that helps.

The MTU from DHCP feature is new (see
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=206721 ) and e1000
interfaces will reset when applying the MTU.

Jim P.