Link flap when adding / removing a vlan (was Re: r360902 breaks VLAN interface on if_em (82579LM))

[mike tancsa]

On 11/9/2020 7:32 AM, Lev Serebryakov wrote:
> On 07.11.2020 2:46, Eric Joyner wrote:
>
>> The other issue is that I still don't know which devices need a
>> restart / which devices do not, or whether a restart is strictly
>> necessary and if there is another way to do this without worrying
>> about restarting the device.
>  Could this be copied from pre-iflib driver? It did right things
> without unneeded resets, including some `em` chips.
>
>  BTW, I'm surprised, that pre-iflib drivers still available on Intel
> site and in ports. And sometimes works better :-(
>
For my specific case (no DHCLIENT and I210 chipset), I just used

--- if_em.c     2020-09-26 07:46:16.474942000 -0400
+++ /tmp/if_em.c        2020-11-09 08:13:55.888378000 -0500
@@ -4047,6 +4047,7 @@
 {
        switch (event) {
        case IFLIB_RESTART_VLAN_CONFIG:
+               return (false);
        default:
                return (true);
        }


And that seems to work for my particular chipset and use case.

    ---Mike