Re: em(4) does not autonegotiate when fixed media is set

From: Lutz Donnerhacke <>
Date: Wed, 02 Mar 2022 16:21:22 UTC
On Wed, Mar 02, 2022 at 04:40:38PM +0100, wrote:
> Is that what is expected? When using the above command I would expect
> that 100MBit/sec is used, not that the card negotiates with the peer
> something else. But my expectations might be wrong...

Negotation of a given subset is useful. Some devices do not work without
negotiation enabled, others refuse to work in this case. Standard requires
autonegotiation for 1000TX, recommends it for lower speeds (otherwise assume
half duplex). For 1000FX the situation is unclear, depends on the year the
device was manufactured ... Today autoneg is expected on all interfaces even
with a limited subset of capabilies.